I gave a listen to your riff and it's a good start.
To diversify a song I might try adding some layers or effects - just throw a bunch of stuff in and tinker about with EVERYTHING.
Then again you might still need other parts - for this particular sample I'd put some drums in too maybe after a couple of bars with a compressor on the main riff to give that ducking effect - but it's all up to you really and what you think maybe even chuck in a vocal sample to give the beat a bit more feeling or something or you could shift it up an octave.
I hope this helps anyway and I'd love to hear the final cut feel free to PM me or something when ya manage to 'diversify' it.
