Roses aren't houseplants; they're landscape shrubs. That's the first problem you're looking at. Secondly, most of those minis are planted 3, 4 or 5 stems to a little-bitty pot so the root systems are long overdue for transplanting.

The rose needs to be repotted, preferably with each root system potted into separate containers. Use a potting soil with a garden mix or rose planting soil, which will have some fertilizer in it. The container needs to have 4-5 holes for good drainage. Although roses don't like to have 'wet feet', putting a saucer underneath the pot and dumping the excess water out of it will keep the water from making a mess in the dorm. Water every other day or so, letting the top of the soil dry out.

Roses need pretty much all day sunlight. Obviously, my Phoenix sun is overkill.

I'd also wash the rose bush/leaves thoroughly to rid it of spider mites and disease spores that accummulate when plants are crowded together in merchandise displays. I've had very good luck with spraying them with Ortho's Rose Pride or Orthenex.

Good luck.