Need Help!!

Hey guys hows it goin? My friend needs help with a problem.. He doesnt know which route to go.. So The other day we replaced the coils in his 2002 Audi A4 3.0L 6Spd Quattro and the rough idle dissappeared. Then yesterday the car started shking again, and both of us were like what the ****? We just replaced them thinking this wouldnt happen.. So whatever we just looked past it, didnt think to much of it.. So ya on our way to school today He was driving fine.. not beating on it whatsoever and then all of a sudden the Check engine light pops on... So we were like ya know ok whats wrong? We continued to go to school. After that we went back to town and brought the car to the repair shop where a friend of our works, he plugged his scan tool in and we went for a ride.. He was showing us the O2 readouts at the manifold and at the cats.. Both werent to well but the ones by the cats were worse.. He got the codes that he needed and we went back to the shop looked thwem up in the comp and say that the cats are pretty much worthles(not doing there job) So anyways he got quoted like $1300 for the cost of the cat and labor n ****.. What we are wondering if there is an easier/cheaper route to go??? All the help would be greatly appreciated.. Also if anyone has an exhaust for this car for sale.. hit me up ski_doo73@hotmail.com... Thanx guys.. Peace