When to see an oncologist after colposcopy shows adenocarcinoma in situ.?

I recently had my annual pap with an OB/GYN that is a new physician to me and it came back with High Grade Intraepithelial Lesions, Severe Dysplasia, Squamous Cell Carcinoma in Situ, and atypical glandular cells. My OB/GYN performed a colposcopy that shows adenocarcinoma in situ. A month later I was scheduled for the hystoscopy (performed today) by my OB/GYN. He said that so far he has not contacted an oncologist. This new physician states that I will definitely be having a hysterectomy, but all other plans will be discussed after these results of the hystoscopy come back. I was told by family and coworkers that I should seek a second opinion since it is taking so long to get an answer. When should I be seeking a second opinion or looking for an oncologist?