Need Advice for Petitioning for 2 Sons!

[kirkfortune]

Hello everyone. I have a few questions on what is the quickest way to get my two step sons in the US as soon as possible. Here's our story:

• I Married their mom back in April 2007 (before any of them were 18)
• The oldest son is currently 19 (born February 1993)
• The youngest son is currently 15 (born November 1996)
• My wife came to live with me in the US on September 2010, she came here on a visitor's 10 years visa from Jamaica, while she was here we adjusted her status and she receive her green card on December 2011.

My questions:

1. Can I have the kids come to the US on a visitor's visa and then adjust their status like what we did to their mom?
2. Will the CSPA cover the oldest son (19) from aging out (if the process takes too long)?
3. How long should it take to complete the petition taking their age into account?

I am really worried about my oldest son, because I really want him to start college here in the US by the time he is 22.

What's the best and the quickest way to get those guys up here with us? Please let me know if you need any more details.

Thanks in advance.