there are actually some excersizes you can do to help increase your bust line. But remember you have to do them consistently to get any results. Here is a site that can give you some good excersizes.
Also a word of advice, dont waste your money on breast enlargement pills. They dont work. And if you do consider plastic surgery find yourself a surgeon with a great reputation and a lot of experience and one that your comfortable with and the better the outcome will be.