Immigration solution

As there's been so much debate in the news of late about the immigration problem from Mexico, I thought I'd offer up my suggestion for a solution.
I think that the U.S.A. should purchase Mexico, and add another star to the American flag. That way, all the residents of Mexico would become legal U.S. citizens automatically, and perhaps they wouldn't be in such a rush to cross the border. There wouldn't be a need, as they would be making at least minimum wage. We'd then build schools down there, and the children would have to learn the English language, hopefully, maybe even better than our current U.S. children do. Nobody would need documentation to drive from Texas to Mexico, we could come and go as we please. Go enjoy those vacation spots, and still be in America. We'd have to build better sanitation and water filtration plants, and hopefully, when we do go on vacation there, we'll be able to drink the water without getting sick.
How's that for a solution?