Adding formula

I'm going back to work on tuesday and my daughter is starting daycare. Based on my breast milk freezer stash and what I've been able to pump I'm going to have to supplement with formula soon.

What brands are recommended. I still plan on breast feeding when I'm home and on weekends. I'd like to start early and mix it with the breast milk so I can try to make my supply last as long as possible.

I do plan on pumping when I go back to work but from when I went back to work the last time I was only able to pump about 8 oz a day at work. I am able to pump before work and the amount varies based on how often my daughter wakes at night to feed.