did you make any modifications? because even opening up the exhaust on RX7's can cause it to run too lean (too much air) which would blow your seals.
what you need to do now is replace the seals with similar or to be smarter use much better ones. get some 3mm apex seals. im not sure where they sell them but im sure you can find them somewhere. also, i think its the same thing with the rotor, although i dont see much in it breaking, its a solid steel rounded-triangle. But threres lots of gears/teeth in there that may wear and im not sure baout replacement if it would be fatal to the engine. if it was, i wouldn't panic:
www.revolutionrotary.com
they sell REMANUFACTURED engines which is like buying a brand new RX7, plus they come stock with street porting, 3mm apex seals, underpully etc, its real nice. plus its only a couple G's
good luck, if you plan on modding one make sure you do research and get an independant fuel system, the guy whos RX7 was in fast and the furious messed his up by just opening the exhaust because he didn't research it first.