If there is still time, take all the summer classes you can! I took 3 easier classes (2 were online) over the summer, and that boosted up my GPA to a 3.53 from a 3.4. Take as many online classes as possible, because it saves a LOT of time. I was able to get 10 units in the course of 6 weeks. I very much preferred that to grueling 18 week classes, although the workload was much higher.
Also, look into petitioning classes you got C’s on. Meet with your counselor and fill out the appropriate paperwork.
Finally, props to you for getting back on track! 
If it makes you feel any better, I was in the same predicament, and was accepted to UCSD with a 3.45 GPA. Fortunately, colleges are mindful of these things and keep an eye out for upward trends.