I don't have endometriosis, but I have two very good friends that do--both have had successful pregnancies, but not with a lot of work.
My first friend used the ovulation kits with both of her sons, but it took a long time--two years with each, and she had multiple miscarriages trying. But she did it without any fertility treatments.
My second friend also tried the ovulation kits with no pregnancies, they then tried artificial insemination without results and then finally in vitro. The In virtro finally worked, but they have tried again since then, and have not had a success.
Regardless though, both of them did become pg--but with a lot of work and patience. So talk to your Dr. and see what options are. Depending on your age, they will recommend the ovulation monitor for at least 6 months and then take the next step (which is usually fertility drugs to help you produce more eggs).
As far as the ovulation kit--just make sure you guys have frequent sex right when you see your surge! You've got about a 72 hour window there--Oh yeah, and don't forget to have fun! No need to take that out of the baby making process--at least not yet!
Good luck!