I read all of the books and started exposing my first son at 6 weeks old to bottles as recommended - always having my husband feed him when he came home from work at 7pm. He refused for a few weeks (exact situation you have with milk dribbling out, and then my breastfeeding), but we were consistent and eventually he caught on.
With our second son, my maternity leave went by so fast that I finally realized a couple weeks before it ended that we had better get him used to the bottle. He was a much better nurser than my first so he was even harder to bottle feed. And since my husband only had an hour after work, he used it to play with the oldest son. So instead of doing what the books said, I fed the baby a bottle around lunch time myself. I tried to be consistent in the time, and chose a time that daycare would be doing it. At first he too let the milk dribble out, and ending up on the breast. Although he wasn't totally into it by the time daycare started, and he didn't eat much there at first, he did come around (if he wanted to eat during the day, he learned to take a bottle). The daycare provider helped tremendously.
I'm not convinced that bottles make a difference, but we used Dr. Brown's. Its more about the consistency, I think.
In addition, if you're returning to work, my advice would be to keep pumping, and start freezing the extra. If you have a little supply prior to returning you won't be super stressed out during the days to get to the bathroom to pump. I wasn't very successful with my first, but learned some lessons for my 2nd. Once I returned, I bought a double pump and pumped twice as long as a regular feeding (this way I only had to pump once a day). I also pumped on weekends and fed the baby bottles to not only keep the baby used to the bottle, but also so that my breasts from getting engorged. Again, consistency is key.
If you have any questions at all, please feel free to contact me.
About me: I work 4 days a week outside the home. I have a 3-year old son and 1-1/2 year old son and am due with baby #3 in late September.