2002 Citroen Saxo Lost gears?

Drove to Oxford and back to reading, car was absolutely fine. Parked up took it out of first and came out easy. Went to put it in reverse to give the person in front a bit of space and the gear stick went floppy and I went forward. I've recently found I only have 3rd and 4th (I guess) and no other gears. It bites in the middle then top and bottom of the gear area it slides both ways loosely. I've replaced gear linkages today because the top one was worn. Still only 3rd and 4th? Quite new to driving and cars so not quite sure what to do. Any suggestions of what I can try, haven't really got the money at the moment for a garage and need the car asap.