My bro, according to the best of my knowledge, U cannot "reuse" an air bag... It has small amount of explosives in it.
Now u need to replace the whole SRS assembly of ur car. Seat belts and the steering wheel.
Don't know where u can get them though.
One thing more, ur steering cover would be torn after the air bag came out. Even if u mange to put the bag back in, u still need to get a new one...