As a proponent of Home-education and a former classroom educator and advisor, I'll advise that switching now is probably not the time (sorry).  Instead, I would focus on getting your GPA up and figuring out how to explain the earlier low GPA in an "exceptions" essay. Even if you started homeschooling now and got a 4.0 (With clear proof a 4.0 was appropriate), it would simply be averaged with earlier work anyway.  Switching to homeschooling does not wipe the slate clean for you.

As already pointed out, it really depends on the specific college and as I understand it, College admissions offices are overcoming former prejudices against home-schooled kids and even seeking them out in some cases.  However, at this late point in the game, leaving the school setting you are in and have been in for 11 years, looks more like escapism than an improvement in your situation on paper.

Focus on over-coming the challenges you have faced in the past so that you can speak about how you over-came them and are a better student now in interviews and in a short-essay response to, "Is there anything else we should know about you when considering your application."

**Consider these alternatives:**

Go meet with your school district's guidance counselor/counselors.  Get the info you need for your goals and location regarding the admissions process as well as brainstorm ways to meet your needs within your district or school's systems.

 - Will your school work with you to grant an "independent study" so you
   can work your way through *The Handbook of Mathematical Logic* under
   the supervision of a cool teacher there at the school.  Then you can
   skip out on Trig or beginning Calc (typical Senior year fodder for
   the college-bound) and not waste your time with it.  You may be able
   to find a teacher who is willing to exchange being your mentor for a
   little help grading changing bulletin boards, making copies or other
   work around her/his classroom?
 - If you are in Washington State look into the Running Start Program -
   which allows highschool juniors and seniors to take college level
   courses (at community colleges) on the state's dime and get both
   high-school and college credit at the same time (GPA applies last I
   knew).  Even once you are in college there will be gen-ed
   requirements you may consider to be a waste of your time.  This helps
   get some of that out of the way too.  I'm sure at least SOME other
   states must have similar programs.
 - Get in touch with [AEGUS][1] (you'll have to join) and see if they
   have any further ideas for you and if they have representatives that
   can help to advocate for you to get a superior education right where
   you already are.

**Finally**

I started my application process during my Junior year (in fact, that was when I took my SAT as well).  I was applying for early admission, but your are behind on this count even when not applying for early admissions.  If you don't jump on getting started very soon, you may miss your window and find yourself relegated to waiting another year, or starting at a college you don't feel is of the quality you would like anyway.  Figuring out how to switch and get a home school education that meets your state's requirements as well as those of your desired secondary institution will be a lot of work and take a lot of time and sacrifice for you and your lead teaching parent.  Getting all of that going while ALSO working through Admissions and then Financial Aid applications is likely going to take a lot of time too.  

  [1]: http://www.aegus1.org/about.htmlhttp://www.aegus1.org/about.html