Try this:
git clone SOURCE_PATH NEW_PATH # clones everything you have committed up to now
cd NEW_PATH # go to new clone, don't modify the pre-existing one
git reset --hard REV # REV is the revision to "rewind" to (from git log)
So you need to figure out explicitly which revision to go back to (Git probably doesn't know which revision you originally cloned, but probably you can figure it out). The first step is just to clone from your local disk to your local disk in a different directory so you can keep your existing work untouched.