RE: Need to know what to pick up or order..
There should be a sticker attached to the crystal itself, that's the important one. They have to match on TX and RX or it won't work. RX crystals are relativly cheap and easy to get new ones at a local hobby store (online ordering will just take too long) Just keep in mind the further away from the channel the RX is tuned for the lower the signal quality will be. So if your RX is marked for a specific frequency on the housing itself that may be the frequency it's tuned for. But again, the crystal is the important part. Replacing the crystal will fix your problem if it's the wrong one.