I lost my Domain name.

[carl@huntingdogtrainer.ne]

I recently lost my domain name by way of a shady buisness company that was supposed to renew it and didnt. I have had to rename my website from www.huntingdogtrainer.com to www.huntingdogtrainer.net . There is a new owner of my old domain name and he is keeping the site even though he has nothing to do with training dogs. My old site still has number one ranking on a "hunting dog trainers" google search. My new site cant even be found. Is there any way to stop this new owner from getting my hard earned ranking and redirect that traffic to my new site. All keywords are the same on my new site and I update it reguarly. HELP!