Help!!! Long post!

First time mommy and my daughter is 19 days old today. In the hospital I was exclusively breastfeeding. 5 days after birth, I took my daughter to the doctor and they said she had lost too much weight (7.7 at birth and 6.6 at the appointment) he said she wasn't getting enough to eat and said I needed to supplement. As soon as I left the doctor I called and made an appointment with a lactation consultant. I had the latch wrong and she said I needed to pump and breast feed. Then supplement if my daughter was still hungry after a feeding. I try to breast feed and keep her on the breast for a long while to help try to bring in more milk. She always takes 2 ounces of formula after the breast. Sometimes my boobs are sore from pumping and feeding so I just give her a bottle of formula. When I pump I only get a half ounce at a time...from both breasts combined. I really want to breastfeed and was wondering if anyone has any solutions for me. I am a stay at home mom with limited income from the hubby (so some inexpensive ideas). Should I pump more? When should I pump? How long should I have my daughter on the breast? How many ounces should she be eating? I have seen the doctor since, but he really wasn't much help at all. Is there any hope in eventually getting my daughter off formula at this point?