I have a similar situation with my upper right molar. I have decided to have my tooth extracted rather than undergo a root canal.
In answer to your first question, you should absolutely have an oral surgeon perform the extraction. My dentist is having an oral surgeon in his office perform my molar extraction and the implantation (if I decide to go that route).
To be completely honest, I would be perfectly happy if my tooth were extracted leaving behind an empty space. The reality is I know that isn't an option for me. Leaving a space would cause the other teeth to shift causing future problems with my other teeth. I am meeting with my dentist tomorrow to have another x-ray (to see if the infection has spread) and discuss my options. I'm not crazy about having a bridge, but it seems a lot less radical than having an implant put in.