Chance of getting into a 4-year university

<p>Ok, let me start by saying I'm not stupid. I've been in GATE (Gifted & Talented Education) and Honors programs since 3rd grade (the earliest my school district allows). But my grades are atrocious. Utterly atrocious. Well, I've never had an F and it's never been to the point where graduation would ever come into question but they're not stellar.
My sophomore academic GPA is a 2.5 (non-academic is a 3.0 because it includes swim and water polo)
BUT before you scoff at my even wanting to get into a four-year with a 2.5 I want to point out I was just diagnosed with ADHD the summer after my sophomore year (I'm currently a junior). Would this diagnosis help me in terms of admissions? Once I was prescribed medication I saw an immediate difference; in fact, my GPA right now is a 4.2. I'm making up Chemistry right now so the D/C I received sophomore year will be replaced and boost my GPA, and next year I'm going to retake Japanese II (I got a C both semesters) and the D I got in AP World History has already been made-up in summer school. </p>

<p>So my question is: Would colleges take in account the fact that I wasn't diagnosed with ADHD and then once I was diagnosed there was an extreme change in accordance to grades? Do I still have a chance in getting into college?</p>

<p>I'm working on fixing my current bad grades and although it will boost my grades the colleges will still see that I had to re-take the courses. I'm taking the SAT next month and I'm going to take it again at least once and I plan on taking the ACT as well. My PSAT score was 189 (would've been higher but I forgot they omitted the fill-in math section if you left the answers blank instead of guessing, dumb mistake) and online it predicts an SAT score between 1850 and 2050. Hopefully I can get over a 2000 with some studying. Also, do extra curriculiars have any substantial influence? I swam competitively for 6 years although I quit this year to focus on my grades. I've also been involved with Junior Guards and water polo and I'm still involved with dance, community service, and I'm a lifeguard and a swim instructor. Do colleges actually take notice of things like that or is it more of a "Hmmm, that's nice" sort of thing.
Sorry this is so long! Oh I live in California and I want to stay in state if it matters. I know it's super competitive.</p>