I would try and find a la leche league meeting, or leader near you. Leaders will often give you advice over the phone. Or see if you can talk to a Lactation Consultant.
When I was having problems with my DD's weight gain, or lack thereof in her first couple of weeks after coming home from the hospital, I had a LC come to the house. She watched K latch on, she also checked her suck with her finger, making sure there was no tounge tie.
One lady I know weighed her baby on a good infant scale before and after each nursing session to see how much her baby was taking in.
Also check out drjacknewman.com and/or Kellymom.com There are lots of good articles on getting baby to get more milk at the breast and Dr newman's site has some videos on what a proper latch looks like and what a good suck, pause swallow motion should look like.
Hope you find some answers!
Sandra SAHM to Kayleigh and welcoming Emily January 2010