Your chances depend on lots of stuff: grades, MCAT, letters of recommendation, extra-curriculars, volunteering, clinical experience, research, personal statement, interview skills, fashion sense, stage presence, star quality, etc.
Your existing undergrad GPA is more permanent than a tattoo. Not only do adcoms WANT to see all your undergrad transcripts, you're REQUIRED to submit them or you get kicked out. (Typically AFTER you've accumulated $100k debt or so.)
There's no such thing as GPA repair, because it's an average. So whatever new undergrad work you do, it gets added in to your old undergrad work and the total determines your undergrad GPA. There are year-by-year breakdowns on the application. Your overall GPA and your science GPA need to be as high as possible, preferably higher than 3.5. Doing a spreadsheet to see what's possible, and how long it'll take to get there, is highly recommended.
If you don't know about the parallel medical education system for osteopathic physicians, you might want to look into it, because it's slightly more sympathetic to the sub-3.5 candidate (like myself).
Lastly, as I learned THE HARD WAY, there's no magic wand you can wave that makes you start getting good grades. Don't assume that you'll start getting a 4.0 just because you want one. Take advantage of every learning skills workshop, tutoring opportunity, study center open hours, etc. you possibly can.
Best of luck to you.