I vaguely remember using a Gmail feature in the past where you could give it your credentials to another account and it would retrieve email from that account and show it in your gmail. I guess it's similar to forwarding, as russellhltn suggested, but in this case, it's pulling your email vs. pushing it from another service. That was several years ago. Maybe a feature like that is still there; you'd have to look through the options. Even if that works, as russellhltn mentioned, any sends are going to be from gmail.