IMHO, I think it really depends on your child. I have heard about exclusively breast-fed babies having a very difficult time when they start daycare because all they want is mama! This puts the day care in a difficult situation because they need the baby to eat! I've seen some day cares refuse to take a child until they are accustomed to the bottle. On the other hand, some babies do just fine with the transition.
When I introduced the bottle, my daughter "rejected" me. :) I guess she liked the faster/easier way of eating better! But the good news is that I was able to pump enough breastmilk to keep up with her demand and that is what I did until she turned one. It was a high-maintenance way of doing things, but it worked for us. One of my good friends, however, was able to do both - breastfeeding and bottle - when she went back to work without any difficulty whatsoever.
I would start with the couple of times a week option and see how she does. If she still wants to breastfeed then try to up it to once/day. Ideally, you want her to get used to taking the bottle from someone else so she won't have trouble when you go back to work.
Congratulations on your new baby!