I'm not 100% sure if you can convert an 360 save to PC.Uhm, just posted this question in another ME thread, but here it'll get more views I think:
You can, however, start a new ME2 PC save, and as soon as you're able, exit the game and use an editor to change it.
http://www.masseffectsaves.com/mods.php
Edit: If you have found a tool to convert ME2 saves from 360 to PC, you should ask someone with a 360 to import your ME character into ME2 and give you the save file.