I had lots of supply issues, but luckily I didn't have to do the formula part. What worked great for me was oatmeal in the morning (I didn't even realize that this had an effect, until I ran out one week), and fenugreek capsules. GNC had the cheapest because they were in bulk, but take 3, 3 times a day. You can up the dose if you need to. At one point I was taking 5, 3 times a day and know of others that did 7, 3 times a day, until the milk came, and then slowing weaning off, taking notice if the supply dropped and increasing again, etc. Warning, you will smell like maple syrup, both your urine and from your pores.
I would suggest going cold turkey off the formula after a day on the medication. You should feel your supply increase, and let your daughter do the rest of the work for you. She should continue to try to feed until she is satisfied, and that should stimulate you more than just pumping. Pumping on top of that can't hurt either if you are still feeling like you aren't up to the ideal supply. This should also make the transition back to the breast easier in that she isn't expecting the bottle and will have to work harder to get what she wants.
You should contact a lactation consultant too, if you have any issues, they have lots of experience and can tell you if you are headed in the right direction or need to make any changes to your approach.
Good luck.