Could someone help me design a 3 day/week workout regimen?

I am embarking on weight loss, and in four months time I hope to have lost around twenty five pounds. I plan to hit the gym three times per week, or more, depending on what you all think would be beneficial..I only have from 6:45 am until around 7:25-30 am so I was wondering what I should do while I am there. Is it also a good idea to swim lengths in the gym pool? I've also just joined a competitive volleyball league that practises twice per week for 1 and 1/2 to 2 hours each time. What else should I be doing to lose the weight and ure that by the end of June I can once again wear that little bikini. Any advice is well appreciated.