| I was trying to think what to say to help you, but I am blocked by the "old stuff" you mentioned because I don't know what it is. Not knowing at what level you have been playing, I cannot advise you as to how to procede to newer and fresher material.
Well, let me try anyway. Whatever style of music you have been playing, how about trying a new style? If you specialize in punk metal, try country. If you specilize in pop, try salsa or merengue. If you specialize in church music, try polka or blue grass. Try blues. Try easy listening jazz (as something tells me you may not quite be ready for more complex jazz).
Or if you know a variety of chords, try scales amd modes. Work on the major and minor pentatonic and blues scales, for example.
If you don't read music, learn how. If you have a four-string bass, try a five-string bass. Try to compose music. Try to transcribe music you like or if you can't, try to play music on your bass you hear on the radio or on your CDs.
Get in a band. There is probably no faster way to improve as a bass player than join a band. You will discover in a hurry where your weaknesses and strengths lie and you will be very motivated to fill in the gaps in your music ability.
Good luck. You are doing the right thing to try to find out how to grow as a bass player.
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"Jazz sounds like a very good blues band that fell down a flight of stairs."
Michael Buble, Canadian standards singer | 
