I took immuno at UC-Berkeley Extension with Dr. Ranes-Goldberg. If you look on the search bar or my posts you can find my review of the course. Highly recommended! I learned a ton and the course load and exams were reasonable. Price tag wasn't too bad either as compared to in house university prices.
They also offer genetics and biochem, however be sure to look up any info on those professors. They're really a mixed bag w extension courses and your professor in these courses is even more determinate of your grade so make sure you research!