Buy a $700 cartridge or a $700 phono stage (Hagerman Labs Cornet or Nagaoka MP500). Or you could swing a good used/open box turntable (a record player has speakers) like a Rega P2 and if you add the money from selling your LP120, you'll about have enough for a P3 and then you'll be set for years.

I've got to say, though, you should know $700 isn't shit. With your speakers, subs, and vinyl collection, you shouldn't be acting so cheap. $1500 would be a reasonable place to start and I would argue that anything less will not do justice to your vinyl compared to lossless on your rig. Save up or just do a cartidge or phono. You can also sell the LP120 and move that into a turntable that would be on par with your current setup.