Congratulations on your success. If you always hated shopping because things didn't look good or you didn't know what to buy or look for to try on and now you don't know your size, consider going to Nordstrom. The salespeople there are really good at helping you find things that work for you and their bra sales people will measure you and figure out the best size and type of bra for you. I do not work for Nordstrom, I just found last time I lost a lot of weight I got overwhelmed easily by all the options and Nordstrom was really helpful. Plus, my mom hates shopping and she would only go there for the longest time because of how helpful they are. It's expensive, yes, but you get what you pay for.
If that's out of your budget, try Chico's. Their staff is also very helpful, but you have to like their style of clothing!