BOSS DR-880 - help!

[The Excession]

Anyone got one of these?

Couple of friends play guitars and do the pub circuit singing country/folk easy listening songs.

They use the DR-880 for backing, in the mix I keep it louder through their monitor than front of house since we haven't managed to program it with anything worth while.

Essentially then it is used as a glorified metronome but I know it is highly rated as a drum machine and I would like to get it programmed with full songs rather than just running a continuous loop.

Can anyone get me going on finding some MIDI backing files for popular songs and getting them into the machine so that it can be used to a fuller potential in the performance?

I'm more than competent using computers and stuff, but my musical skills are no where near good enough to start creating full drum patterns for songs.

We're happy to run a sequencer on a laptop an drive it via MIDI if needed, but putting some songs into the machine would be fine just to get us going.

Also, don't mind paying for MIDI files once we've got the hang of setting it all up.

Any advice greatly received
Thanks