Replying to Intermediate Codecs in MPEG Streamclip for PC?

Like many NS'ers of late, I have hopped on the GoPro HD bandwagon for this season. So far I've been very impressed with the cam, but now I need a way to convert my raw files (shooting in 720p 60fps) into something smaller that won't fill up my hard drive in a few weeks and that will run smoothly while editing. I've heard that Apple ProRes is a great codec to use for this purpose, however I have a PC and apparently you cannot convert to Apple ProRes if you're using Streamclip on a PC. Do any of you filming/editing gurus have some suggestions for a codec in Streamclip that I could use that would give me results comparable to that of ProRes? Or any other programs/suggestions for that matter. I will be primarily editing with Premiere Elements 9. Thanks for any help.