It would have been better to come to ask for advice BEFORE getting the DJM2000 Nexus. Apparently you went and bought the mixer that even most pro’s don’t use (the DJM-900 Nexus mixer is by far the most popular with pro’s), already knowing that you couldn’t afford the CDJ2000 Nexus players.
Obviously you can get some low(er) end CD players to go with your mixer, but that would be a waste really.
The same money you have spent on the DJM is what would have gotten you the DDJ-SZ, Pioneer’s flagship controller.
It’s not clear to me how experienced you are as a DJ (although I have an idea :-), but unless you are experienced, I would not even recommend the SZ yet. Half the money gets you the SX2 which is a plenty good controller for all but the most demanding of DJs.
Is there any chance you can go and refund your 2000?
Be sure to tell us some more, so we can help you better.