Continue looking for a job until you find one. Don't give up. You don't have much choice really but to continue looking. Don't make the fatal mistake of "hiding in school" and taking on a bunch of unnecessary debt and investing time in a degree program that you're not interested in simply to "pass the time". Yes, the job market sucks and it's hard. But you're just going to have to continue trying.
Getting an MBA without work experience will not help you at all. And with a lower GPA, it won't be fatal for b-school admissions if you have a few years work experience, but right now with a lower GPA, some volunteer experience - you don't have a lot to offer to a b-school right now.
I know this may be hard to hear, but don't give up on looking for a job.