I think you are setting your sights too low. A combined score of 25 won't get you into most medical schools, including some osteopathic ones. These days, you ought to shoot for a combined score of 30 or higher for allopathic, or 27 or higher for osteopathic. This is a formidable task, in my opinion, especially after a period of 10+ years away from school. If you do not retake your premedical prerequisite classes, or take additional advanced science classes, I think it will be even more important for you to perform well on your MCAT.
The medical school process isn't a sprint, as I've heard it said, it is a marathon. Don't rush. Do what it takes to do it properly, even if it means retaking a majority of your premedical prerequisite classes. The MCAT is both a critical thinking test and a test of your knowledge. You have to know the basic sciences well and be able to apply the concepts in unfamiliar situations under extreme time pressure. Kaplan wouldn't be enough in my opinion. You would need to fill all the wholes in your knowledge until you understand the concepts like the back of your hand; it's up to you how you want to do this, but you'll definitely need to do lots of problems. Take as many practice tests as you are able to under real conditions without vomiting. Also, do lots of reading with the intent to summarize and capture the gist, especially complex science and humanities articles. Be able to interpret graph and data well. Practicing under realistic test conditions is one of the keys to performing well. Get all the AAMC tests and any other realistic practice tests you can get your hands on and do them all.
Good Luck!