First off, keep your head up! Where there is a will, there is a way! :) I know its easier said than done, but there are ways to help your situation...
I would definitely retake microbio (granted you may face some issues with schools who dont allow retakes, but many are fine with it) CC's are a great place to do that, in terms of saving $$.
Apply to a whole bunch of programs ( ASN, BSN). All programs have their strengths and weaknesses, but its very important to just get yourself out there, so that YOU can hopefully make the choice where you end up. You never truly know what each school is looking for, and although you make think one school is harder, or more strict, they may be intrigued with your premed degree etc. Basically, dont scratch any program off the list yet without more info.
Make your resume look as enticing as possible despite the lower grades. Whether you have volunteer experience, internships etc include everything and if you havent, see if you have time to include such an opportunity in your schedule. The CNA track will not only help you, especially in your clinical skills, but will also look great to the nursing schools.
If any of your schools offer an optional interview, take it!!! Explain yourself ( without going in too much detail) and ask great qs and show interest. Its just another way to look great and interested. Lastly, if they dont offer that option, see if you can go in for an open house or tour, and talk to someone in person :)
Sorry to ramble, hope this helps! Good luck!!!