I'm feeding my baby breast milk exclusively through pumping because we've been having a lot of…

I'm feeding my baby breast milk exclusively through pumping because we've been having a lot of problems with her latching she's only 12 days old so we're still working on it but I pump to make sure she's only getting breast milk. My friend bought the pump for us a lasinoh double electric. But when my breasts are full the suction isn't good because the Funnel things aren't big enough. Which pumps do you guys use. Looking for something that will give me the most milk in a short amount of time. I pump every three hours and definitely am not getting as much as I think I potentially could.