I agree with @toodee. A 2nd filter would be a much better option than another oscillator. It allows better positioning in the sound spectrum (so your track is more 'readable'), it can tweak the sound in a way that an oscillator can't, and it can even become another source of sound (if really needed...) through self-oscillation. The choice of filter, however, will depend on your musical orientation...

'On ne devrait jamais quitter Montauban' (Fernand Naudin).