5th and Rev. GONE!?!?!

I was driving home last night, cruising along in fifth and then downshifted and when i went back to fifth .......nothing. It was GONE and i later found that reverse was gone too.  Whats wrong?  I imagine i need to get a new tranny so will any other tranny's be compatible?  Say, a six-speed? PLEASE help!!

[MyFirst240SX]

Mine did that b4 my clutch burned out

[rampid360]

Linkage is shot.  1st and 2nd are on the same linkage,  3rd/4th     5th//reverse.   If those 2 gears aren't working then the linkage needs to be repaired/replaced.   (i'm basing this on something i've heard...i'm not certain....perhaps someone can help further.)

[JoseS13]

5th/rev shift fork