MC cartridge?

I recently purchased a Marantz 6110 TT on e-bay for about $70. It has the stock marantz arm and a Grado black cartridge. I sounds decent, but lacks the detail I would like. I am considering trying a MC cartridge. I would like to stay around $300. Also, should I upgrade the arm? If so which one? I have been out of the analog game for a while now and I'm trying to tip toe back in. In a nut shell my question is should I upgrade this table or start over with a better table? Thanks for any advise you can give.

Associated equipment....
Conrad Johnson PV10 with phono
(2) ARC D-130 amps
CAL cd transport
MSB gold link DAC
Nakamichi RX 505 tape deck
Nakamichi CR5 tape deck
Martin Logan SL3
Velodyne FRS 12
All Audioquest cables