Hi Babymiracles,
You are having a tough time of it. Truth is, your little one is doing pretty well - just about a tablespoon a week below what you would expect (usually aroud 150 + in the first weeks) and then she's doing "fine" in the last couple of weeks. After 12 wkd it is normal for babies to gain 80 -130g per wk.
The secret is in feeding her (ideally from the breast) more often. Imagine having to get 750 ml into a jug -but you've got to do it by filling a port glass (the size of baby's stomach) and then tipping it into a jug. You are going to have to fill that port glass a lot of times. She needs to feed at least 8 -up to 12 times per day. Even though she takes less at each feed she will take more over a 24hr period.