I also think there have been studies on the "power nap" that show to get a little recharge, then you should limit nap to around 30 mins. That way you get a bit of rest, but don't usually get to REM sleep. When you get to REM, and only stay there for a short period, usually you feel worse than not napping at all. Try to get another hour or so at night if you can and take a shorter nap in day.
If you workout after work in afternoon, then don't nap. I would think that 2-3 hours of sleep after 230pm but before 11pm or midnight would wreck a good nights sleep. Skip the nap and add it to bedtime if your schedule allows.