Although your science GPA is in the 3.0 range, it will need to be improved. Science majors should have higher science GPA's. Now if you were a non-science major, adcoms may be nicer if you were +/- 0.1-0.2 from the average science GPA that science majors get.
An MCAT score of 17 will probably not get you into anywhere, and especially if combined with your science GPA. At the very least, you better have a good reason for getting a low GPA such as working to support your family. However that doesn't explain the MCAT score too well, and stating personal challenges still require some proof of improvement (ie: A's during post-bacc or high MCAT score)
As stated in previous threads, if you studied for the MCAT, and got a 17, then based on statistics, most people will only improve by 1-3 points taking it the second time. Althougn not impossible to improve by larger orders of magnitude, its pretty rare. The national average for those that got into med school is about a 28 the last time I checked, so you will need to improve by at least 11 points to meet the mean. On top of that you will need to have good section scores. So still pretty crappy if you get a 6 on VR, and the remainder being great science section scores. Of course, meeting the "average" doesn't guarantee much either since there are many that score higher than the mean.
Post-bacc programs that have linkage to some med school often times are very competative to get into, and require a good MCAT score anyway. Scripps and Mills college in CA link to a few MD schools. However both require you to take the MCAT again as part of their program, and for Scripps, taking the MCAT already disqualifies you from even applying into the program. Most official post-bacc programs also require some MCAT score of 8 per section. Reason being, they want people that are likely to improve their MCAT score based on the reason I stated in the last paragraph.
Although I am not trying to discourage you, however an MCAT score of 17, and a low science GPA will hurt you greatly when applying. I understand that getting in through whatever means possible (such as a post-bacc program) sounds good, but you will need to ask yourself. Based on your science GPA, and MCAT score, will you succeed when taking exponentially harder science classes in med school, and passing the USMLE step 1, which tests all you learned as an MSI and II.
If you do not have the academic foundation to do well on the MCAT, or in post-bacc courses, then the adcoms will have a hard time dealing with your academic capabilities for your MSI and II years. Traditionally, those with low GPA's showed they had a good understanding of basic sciences (and verbal skills) by destroying the MCAT. I have seen people with 3.2-3.3's get in because they got 35+ on their MCAT. At the University of California, they treat MCAT and GPA EQUALLY, therefore being deficient in one will hurt you, let alone being deficient in both.
