I would suggest Softball as a natural addition since you already have Baseball. According to the NCAA, there were 399 Women's Division III Softball teams in 2006. For 2006, the number of players in lacrosse vs. baseball/softball were as follows:
Men's Lacrosse: 4,349
Women's Lacrosse: 3,114
Men's Baseball: 10,656
Women's Softball: 6,754

So, 17,000+ for baseball/softball; 7,000+ for lacrosse. This should be an easy call. I'd love to see Softball added for this spring. While you're at it, could you get the domain name, D3Softball.com?