How do I get my tubaligation reverses?

Difficult. Tubal ligation reversal is difficult and expensive (usually not covered by insurance). Furthermore, the likelihood of a successful pregnancy afterwards is fairly small. If you still want to go for it talk with your primary care doctor or ob/gyn and they can refer you to the right person.
Infertility doc. Typically an rei specialist (infertility specialist) does tubal reversals. Sometimes a general gyn will have that kind of expertise in the area. Speak to your gyn. It involves surgery, sometimes it can be outpatient. Unfortunately, it is not always successful, and many reis (reproductive endocrinology & infertility) will suggest ivf instead (where you don't need a reversal).
Surgery. There is a procedure for reversal of tubal ligation called tubal reanastomosis. It is not covered by insurance and it costs around 10 000 dollars. The bad part is not is not 100% successfull. After this procedure there is a high risk for ectopic pregnancy.