General care at
www.russiantortoise.org
If the tort looks healthy with clear eyes, no wounds (be aware that tortoises can have shedding skin and still be healthy), dry nose, no wheezing sounds (torts do make a hissing sound sometimes when they retract the head), etc., then you could consider taking it in.
Don't plan on keeping it in a small tank. I really recommend at least 6 sq ft of floor space. Try to make the environment interesting, with places to crawl over and under. Keep the enclosure warm, with a hot spot (during the day) at about 90-100F. Overnight lows can be just room temperature.
Feed it a varied diet of greens and weeds (from a chemical free area). Soak it regularly when it is living indoors.
Come back if you have any questions.