What does your resume look like? Does it show your qualifications? Typically, if you're not getting calls, it may because of your resume. A 3.1 GPA is fine - I've found numerous internships (with interviews) with a 3.0 GPA my second year of college (as an EE major). It went up after that, and it's been relatively easier to find an internship. I'm not worried about finding a job.
An internship experience is fantastic, especially that it was a year long one.
Also, where are you applying? If I were you, I'd apply to anywhere you can, at least for your starting job. Here are some company lists I've found that hire engineers:
FORTUNE 500 2006 - I just go through the company list and then find their careers website and apply through there
Defense contractors - SourceWatch - list of defense contractors
List of computer hardware manufacturers - Wikipedia, the free encyclopedia The College of Engineering @ Iowa State University Career Center - What Can I Do With a Major In...? - scroll down for companies
Technology - Google Finance - technology companies
If you want me to look at your resume, drop me a PM.