You could knit a swatch to convert but what sometimes works well in this type of situation is to simply knit a smaller size...because your yarn is bigger and you will be using bigger needles you can follow the pattern for a smaller size and it will automatically turn out larger. Just figure out the gauge for the new yarn and see how much % bigger it is than what is called for in the pattern.
As far as the bust, you could add short rows or darts http://www.knittingdaily.com/posts/tops/138-1.html
or simply add more increases after you get past the waist. Since the sweater is for you, you can try it on as you go which will really help with the sizing.
The book big girl knits addresses methods for dealing with bust sizing...it might be a good reference for you too.