Pull up the shifter boot and look to make sure that both arms are still connected at the bottom of the linkage. (there is a bushing that can wear out and cause it to come undone)
then, open the hood and look on top of the bellhousing, between the TB and the battery but further towards the firewall.
You'll see the two shift linkages going in to the bellhousing, check that they are still connected there, and have a friend move the shifter left to right. one should move. move the shifter up and down, the other should move.
if they are STILL moving at that point, then you likely sheared a bolt inside the shift tower, and will have to remove it to repair. this can be done WITHOUT dropping the tranny, but don't move the car any more than you have to. You've got to find the sheared half of the bolt, still, down in the tranny!