Hi Bronboots,

well, the obvious sun loving plants that will grow well indoors are pelagoniums, you can't go wrong with those as long as you don't mind the petal drop as the flowers fade. Also, Buzy Lizzies are quite good for indoor use, and Tradescantia will add some varigated foliage as a contrast to the flowers and will trail over the sill if you have the right situation for that, not over a radiator. You might like to try Steptocarpus, it's a slow growing plant but does have rather long strappy leaves that will spread a bit.

Coleus would be worth a try too - keep pinching out the flowers when they appear though, they're not much to look at letting them flower means the plants get very leggy.