If you plug it in and turn it on, does it seem to function correctly (arm moves back and forth, you can hear the "whir" of the motor working)?
I'd probably give the Lactina a shot. If it doesn't do what you feel it should, you could rent a Symphony for $55 or so a month or buy a PIS from Babies R Us or similar.
Just remember that no pump, hospital grade or not, is going to get the amount of milk that your baby can get. And every mom makes a different amount of milk (your pump output will vary from session to session). Getting just under an ounce to a couple of ounces is quite normal for the first month after birth, for instance. :)