MCAT in July or August?

Ok so here's my problem. I am doing my undergraduate degree (biochem) in 3years. This means that now, after my sophmore year I would have to do my MCAT. However, I can't do much else but take the test late, or in July, when I was planning.... because I have done as much as I can in the given time. I have taken practice tests. My highest score has been a 26. If you add up the highest scores I've obtained in each section it would be a 32. I need at least a 32 to get into my choice of school. My GPA is a 3.63, which is okay. Now my question. Should I reschedule for the August exam? I feel like a month would allow me to prepare so much more. I don't feel like the three weeks I have left will get me to my desired score. Will it be completely detrimental to my chances of getting into med school... (since scores would be released in September...)? Please give me some insight.