You'll need to pop your sdcard out and into your computer to copy files to it.
Last time I used the app androot to get root. Then install superuser. Then install a custom recovery with rom manager (app). You'll probably need an older version of rom manager. The newest one isn't on the market for android 2.1 only the pro key is for some reason.
After that put a custom rom on your sdcard (or beforehand) and reboot to recovery through rom manager. MAKE A NANDROID BACKUP just in case. Then wipe and flash your new rom. Be happy.
For custom u can get it from here
Hero, G2 Touch Android Development - xda-developers i personally prefer Elelinux Rom
here i Attached CWM rom in apk format
Thanks to XDA developers tested by me
