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
tbridges8ce4
Terrific step adding an analog rig to your system, but I can't help but think your turntable is not in the same league as the rest of your gear. Hopefully you won't be offended by my observations. I'd consider selling the Marantz and finding something of somewhat better quality, the good old "garbage-in garbage-out" theory. Perhaps a used Rega, SystemDek, or even one of the better Thorens? I'd then follow the suggestions of the folks here as to suitable/affordable cartridges to mate with your 'table/arm. It doesn't have to break the bank and WILL sound better than any digital sources out there. Welcome to the dark side!
marakanetz is right on the money, that is, don't spend any on the turntable, but money spent on a cartridge is not wasted. One word of caution though, what will work well on one turntable (such as a modern one of good mass, with an arm of good mass) might not work all that well on something like what you have. But it is fun to find out. I have found that some of the old turntables actually work surprisingly well compared to some of the cheaper, high end turntables available today. I'm not saying that you shouldn't upgrade your 'table, I think you should, but it shouldn't stop you from getting a better cartridge.
I would set my aspirations to a cartridge that seems appealing to you, and one that would seem to work well on a table that seems appealing to you. What is there to lose? So long as you are willing to accept a table upgrade in the future, willing to accept that your present table may have limitations, the only chance you would really be taking is that your present turntable might or might not sound good, while you look for a turntable that you really want. Judging from the rest of your system, a better table is emminent. You could be looking for both a better table and a better cartridge.
Thanks for your help. I think I am going to keep the Grado I have now, and start looking for a better TT and cartridge set up. Perhaps an LP12 or a Sota. Again thanks for your help. I can always put the Marantz table in the bedroom and my wife can use it (she can't hear anyway).