A couple of things from me. Firstly, the cornice painted a yellow makes the ceilings feel lower than necessary, paint them out white or as per tour ceiling rather than accentuate the highest perimeter moulding, you don't want yo draw attention to the highest detail not being high! Secondly, to make the room feel fully addressed the window has to be looked at in context of your room. The house style is important, but more so the room space and light. As you have a verandah you probably have in direct sunlight, but the room is not large, so i would try to make the window feel part of the bigger picture rather than contrast with it. Which is what the red does, effectively looks like a red rectangle dominating a small wall. Do the opposite, taking colour cues from the room will make it feel unified, therefore bigger. The caramel carpet, for me is where I would draw upwards from. I suggest a rattan roman blind, the texture and stiffness will resolve that terrible sag, let in diffused light and provide a natural element needed in country style schemes. It allows the scenery to stand out, and colour is easily built upon it. If you need further blackout, you can install a uv cheap roller blind within the window frame, which would be hidden from view by the roman blind, so it can remain up most times and the roman can frame the beautiful view, allow light and then use the roller as your night privacy blackout blind. Most Romans look best as a frame treatment, they dress the window better than they function on them. Shutters would also be stunning with their play and filtering of light, but costly. And just a tip, your bed would feel far more luxurious in that space if it were not heavy in colour, the metal and timber, both which are not genuine as in fake cast iron and artificially stained orange pine date your space, that is not a dig, just an observation. You could do an upholstered bedhead for a luxurious look that a linen would tie in with the soft furnishings, you can address colour in many ways, but the blinds, carpet and bedhead should be neutral unless you can afford to upgrade often?.. A layering of texture and tones rather than colour is far softer in a country space, that's why it's done often, creamy whites on a caramel carpet will really brighten and freshen that space, , timber lamp bases, fabric shades, plush pillows and personality pieces, you'll have a space you can't wait to get to. I hope this was helpful!

I found a website that might be quite helpful for you http://www.colourtouch.com.au/ to visualise what colours and finishes could look like on your house. You can choose a style of house that closely matches yours then choose a number of set schemes, or start with a blank canvas and play around with any colour / finish you like.

I actually love the combination of timber, jute, rattan or patterned blinds with white sheer curtains. It's especially lovely if you want the option of either blocking light or letting the most in without letting your windows look too naked. These photos may help you decide:

It's a bit difficult without an image to give me an idea of the areas you are wanting to treat and the overall look and style you are trying to maintain or enhance. Typically, curtains and Romans can work very well in combination within the same room and even with the same fabric as this image, I think, illustrates: The use of pelmets (box cornices) in combination with the curtain treatments and Romans help tie-in the two treatments and help balance the stronger shape, line and form of the Roman's on their own. I agree with @chookchook2, the use of coordinated fabrics is preferable, if that is an option that is open to you. Also notable with this image is the use of a Roman and curtain in the same window treatment. Another example of the use of curtains in combination with Romans. In Australia, it is unusual to have unlined Romans. Soft traditional lined Romans are more typical here, and please ensure that the Romans you purchased are lined with pre-stiffened proper Roman lining and not the much cheaper curtain lining which can lead to 'sagging' over time. Rest assured, it is not at all uncommon for Romans and curtains to be used in combination.