I am going to throw out some names of schools that I think have a decent to excellent chance of falling within your budget, are medium to large (closer to medium, though), that offer not just CS but other related fields (computer engineering, electrical engineering, cybersecurity, etc) so it appears as though there is some relative strength in those departments, but I will leave that for you to judge. Also, since water polo seemed to be a pretty big interest of yours, all of these schools offer water polo as a club or intramural (or both).
Gonzaga (WA)
Colorado School of Mines
U. of Dayton (OH)
U. of San Diego (CA)
U. of Portland (OR)
Creighton (NE)
Bradley (IL)
U. of Denver (CO)