Optimal Environment

A few months ago we purchased a small fish tank for Lillian and tried out a few different species with minimal success. After doing a tank 'cleanse' I bought a few guppies to fill in the tank (we were still far under the healthy recommended minimum) because I had read these fish were hardy and fascinating so I was eager to try my hand at raising a few. We no longer have 'a few'. With the 7 juvi's who survived a drop a few weeks ago, along with the 10+ new tiny babies, we are fast running out of adequate space for Lillian's tank. Anyone have ideas on how and where to relocate these new specimens?