In a similar boat, from what I've read it's
1) Get a power amp, no replacing that, especially to drive Maggies. Odyssey would be fantastic. I got a pair of used monos for ~1200.
2) Get an AVR with 'musical' preamp and preamp outputs. Anthem MRX x20 series fits the bill, and apparently so does Yamaha Aventage 1070/80+ for the remaining money.