Removing your root with a bad ROM will not improve your situation. But you're not out of luck, here. If you can follow step-by-step instructions, we can get you back to operating condition fast. But first, we need to know some things:
How did you root? What Froyo ROM are you using? What is your baseband? These things will be in Settings--> About Phone.
Once we have an idea of where to start, the destination will be easy. I would suggest TheUltimateDroid 1.0.0, which is available in another thread, since it is the most up-to-date and most customizable ROM out there (IMHO). Download the ROM to your PC, move it to the root of your SD card, and then go into ClockworkMod using x+power. Wipe data 3 times (this will wipe your cache too), and install zip from SD card and choose the UD1 ROM. Let it load and log back into Google once you reboot the phone. From there we can tweak things, but does this help you at all?