Pumping advice

My baby has just turned 11 weeks ive been ebf since birth but have decided to start expressing so eventually i will wean her off the breast during the day and give her my breast milk out of a bottle, i tried last night feeding her of one side and pumping of the other to try it out, but only got just over an 1oz, i was expecting alot more as my baby girl sleeps through from 10pm until at least 5am most nights, could it be the pump and what pumps do people recommend i have got an electric one to try later so fingers crossed it works better for me.