eutaketti,

well, if you are good in maths and your writing english is also pretty good, then you are already prepared for quant and analytical part.  if i were you, i would take pre test first, which you can take from preparation cds, and look yourself where you stand.  you will know what needs to be improved.  your score not gonna change a lot, so if you can score descent score in your pre test, i would suggest you to prepare sometime and focus on ur MCAT.  alright, good luck.