1) get back out and do the group rides between now and your first race. Try to mix it up in the sprints, attack the group, run down people who attack.
2) use your commute to do intervals, i.e. go all out from one stop light to the next, then easy to the next light. Sprint to beat the Yellow light, etc. "informal" intervals, or fartlek, can be good workouts, and a little less mentally taxing.