The more you stimulate the breast, the more milk you will produce. I would continue to nurse the baby whenever you can, before you give her the bottle. The suckling will signal your body to produce more milk. If you are afraid she isn't getting enough, give her the bottle after you let her nurse vigorously for 15- 20 minutes on each side. You will notice a decrease in supply whenever you decrease feedings, but rest assured that she will get enough. Your body will produce exactly what she needs. If you have breaks at work, I would also pump whenever you can, this also helps stimulate more milk production. Even if nothing is coming out, it helps to stimulate more milk production. A great book to read is Nutrition and Fertility Cycles by Sheila Kippley. Also, check out your local Laleche League, and www.ccl.org for more great resources and help.
I know it seems like hard work, but it is so worth it. Your baby will benefit so much, both nutritionally, and emotionally.
\Good Luck!