Like aussienic suggested the singlets that button up are fantastic for winter babies. They keep their backs covered and toasty warm. If you are thinking about wraps I didn't actually buy any wraps I bought cot sheets and folded them in half as wraps when they were newborns and then shortened the overlap fold as they grew. Saved us a heap and if bubba doesn't like being wrapped you haven't wasted your money as you can use them on their cot. Having a winter baby I would definitely suggest a beanie/hat for going out. They get so cold if their heads aren't covered.
Like the other girls have said the one piece suits are fantastic. I would work off around 5 -6. You may just need to wash more regularly but totally doable. There are some gorgeous little suits around now so you don't just have to get the plain colours. You have got heaps of time so wait for sales and layby things so you can it off slowly. Also look for bulk packs too. Shop around for the best prices. Takes a bit of time but can save you heaps in the long run.
You will need a few blankets (2 or 3) depending on how good you are at washing and drying clothes.
Best of luck darl. Enjoy shopping for bubba.