If you haven't really done much studying at all (in other words, you basically took this test "cold"), then there's a decent chance in general that you can do what you need to do in order to improve your score substantially. It will be challenging to do in 5 weeks, though - most people take 2-4 months (and sometimes longer) to get to where they want to be.
Your verbal looks great (especially if you took it cold) - there, you may just need to get a resource for grammar and study it yourself.
For quant, you obviously need a more comprehensive plan. I don't know whether you've though about how you want to prep (whether on your own or with a class or tutor). Most classes run longer than 5 weeks (though if you happen to be in NYC, we hold a 2-week Boot Camp, during which you meet almost every day for 2 weeks, and for the following week, there are office hours during which you can ask questions). If that sounds interesting to you, take a look at our web site for details.
Otherwise, you're looking at either self-study or private tutoring. For the self-study, there are multiple options. You can get whatever books you want from whatever sources you want and set up your own study schedule based on your strengths and weaknesses. MGMAT also has a couple of Guided Self Study packages that include a syllabus, all of our books and online materials, and other things. One of those packages also includes tapes of the 9 class sessions, so if you felt you wanted to get some instruction but just didn't have time for a live course or money for a private tutor (which is very expensive), then you could use the tapes. Again, if that sounds interesting to you, take a look at our web site for details.
There are three books you have to get no matter what you decide to do: the three Official Guide books. These contain real, past test questions. You can get them on our web site, on
www.mba.com, at Amazon, wherever. You should also download the free GMATPrep software from
www.mba.com.
Also, given your quant percentile, you may want to look into our two Foundations of Math workshops. They're meant for people who haven't done math in a very long time and want some extra work to get up to speed before a class begins. Depending upon why your percentile is what it is, you may be able to get yourself up to speed on your own using the books, or you may want some extra help with that. Again - details are on the web site.
Good luck - let us know how it goes!