[iceblue]

Taking into account the head preasure I would go for 500 - 600gph circulating through the tank. Same thing with the jet system. You will want between 100-150gph per jet.

Here's a calculator that can help you figure the size pump that will work best. http://www.reefcentral.com/calc/hlc2.php

 

[iceblue]

If it has just the one overflow you could use something like a mag 7 and be well within bounds of your overflow.

Here are some pump head charts that might come in handy. It has a list of the most commonly used aquarium pumps along with thier head loss charts. Click the "more info" to the right of the pump and you'll be able to determine which pump is best suited to your needs. Without being able to see your return line I would guess your pump will be fighting 4-5 feet of head pressure.
http://www.reefs.org/library/pumps/