You don't really have to download the game again.
Just run FHSetup.exe again from the first time you downloaded it, and have it install to C:\FeralHeartBackup or something, then copy the textures that you need over to your actual FeralHeart.
It always helps to have an original install handy, in case you tend to mod your game a lot. /guilty
Aha, good luck. c: