Check out these pumps:
http://www.stenner-pumps.com/?gclid=...FZFefgodUL4AjQ
I got the dual head, 100 gpd one that'll be controlled by my Apex, but you can get much smaller ones. The dual head pumps make sure you don't get variation between your out put and input.
I did order mine out of the states, (it's been a while) but I don't remember the charges being too outrageous.