Original

Site plan

One

Second idea

I've never renovated in my life so need all the help I can get 😉

can you post some external photos, a google earth view of the roof, the missing site plan, what are the walls, floors and roof made out of, where is north and describe your climate..and there are some edges of the plan missing with some of the dimensions can you repost the plans in section so all the numbers along the edges are visible

site plan

site plan

Google earth

double brick and tile

our house is the front house on the Google Earth. with all the trees, palm trees etc in front yard

front of house

climate is warm. western Australia.

the last photo shows a room instead of the original carport..how do you use that new room and does it have direct access into the house?..and the plans show what looks like another carport on the right hand side of the house..what is that built out of?

That is a small budget for such a big wish list. So will need to be smart and prioritise.

Going by real estate photos of your home, the carport is actually a brick enclosed renovation, with a tiled floor. This is a space that could be major part of a good renovation. Your plan said carport, but really it's a good room under the main roof structure.
The minimum set back line is showing on your site plan, unless it has changed from the 1980's when the home was built, you do not have enough room for a double garage at the front. This would be worth making a phone call to council, to clarify.
You already have all the rooms that you require. The kitchen meals area would be the only major change. Looking at your photos, you may not have enough room for extensions at the rear, because of the swimming pool. Noting that you probably have a concrete slab, so any changes in the kitchen, with electrical, plumbing and gas will be costly, but doable.
Just by moving the master suite into the enclosed carport and using the vacant space between carport and the dining for a ensuite, may be a start.

Rearranged internal

the house already has 4-5 bedrooms, 2 bathrooms and 4 living areas and already doesn't suit your family and that will only become more challenging as the kids grow older.. there's no space to add a double garage and mudroom, there's no where to expand the existing bedrooms and even if you moved the bedrooms upstairs there's still no where for the garage..hard to believe but you can easily spend your whole budget rearranging some rooms and updating the kitchen and bathrooms but you still wouldn't have the garage and bigger kids bedrooms unless they move into the other rooms or you build out the backyard and then how would you use the old bedrooms..much as i love a good reno i suggest that your budget would be better spent on a different house but some basic suggestions could include a rear extension (subject to the building ratios and correct setbacks) could be about 40sqm to add 2 bigger bedroooms, and a new laundry, use old laundry for more storage in bed 3 and a better bathroom, remove the wall between games room and old kitchen to create a more generous kitchen, dining and family room with better connection to outdoors, add a new ensuite and use old study as wiw, raise the floor in the old living room and add closeable doors for adult living and enclose the.entry porch and add a new entry to rumpus room for kids activities...based on very rough dimensions but could be something like this but assume at least double the budget and there's still no garage

Another wonderful plan oklouise. But in order to do the extension at the back of home, the swimming pool would have to be removed.

Kate, as mentioned previously, you need to be aware of set back rules, and the 50% building ratio for your land.
You have enough rooms already. If the size of these rooms do not meet your requirements, then it might be time to move. Unless you can see the advantage of overcapitalising to get your wish list.

And by real estate photos, there is already wonderful double wood French doors going from front enclosed carport directly into the dining room.

the problem with the doors between dining room and old carport is that it makes the dining room into a thoroughfare and stops the dining/living room being used as a private space and of course i assumed that the two bedrooms at the back were more wanted than the pool..adding more bedrooms on the other side of the house would mean adding another hallway and bathroom and doesn't improve the existing bathroom for three kids to share with guests...i'm thinking that there may be good reasons to restore the original garage and will have a think about that!!