The pump is a Sta-rite JWPA5FL-2A2. Unfortunately it's not listed on the manufacturer's site (http://www.starite.com/). I couldn't find any flow info in the manual so I'll transcribe what I see on the label.
Another note: the pressure gauge on the tank reads 15psi. Last year, when it was closer to the pool, it averaged 10psi. I'm not sure if that's an indicator of what the issue may be.