The most important point here is to decide what chemotherapy you need. This is the job of the Oncologist. I am sure you trust your Gyn but they are not experts in prescribing drugs and monitoring side effects etc. Also you need to get the drugs in a properly operated environment with trained nurses who can handle issues and answer questions. Chemo can cause allergic reactions so you need people around who deal with this stuff every day. These nurses will also monitor you side effects and adjust your treatment as required.
I would not want anyone else but a Oncologist to properly perscribe and administer chemotherapy>