You should be able to run another cab with that. I think best option for you would be a MAG210 cab, essentially what you have already without the head in it. What bass do you have ? For slap on that i'd boost the high mids and treble to about 2/3rds and change the bass to suit, leaving the rest flat. The bass and treble boost will probably bring a lot of sound out too, i'd turn them on.