speedometer stuck

I bought a 98 civic ex real cheap because it had been stolen and had some small issues, when i first got it, the speedometer worked sometimes but most of the time it would stay on 20, just twitch around like it was trying to move. For whatever reason, sometimes I could get it to work if I would hit the trip reset a bunch of times, but it would stick back on 20 after a mile or so. I have taken the gage cluster out and taken the needle off and put it back on, now it is stuck on 0 and twitches the same way,
am I just gonna have to buy a new gage cluster? is that the problem?
and if I do, what will happen with the mileage, do I just get stuck with whatever the new one says, someone please help me out.....