Hi, that's a nice size enclosure for one sulcata at this age, mine
started with a 300 gallon and that lasted for 3 years, then he required
a 1000 gallon and after a year he's now outside in his own
building (see some pictures in the forum below where I posted
named - Basking in January) to see his cottage. My sulcata is
a male, over 50 pounds at 4 years old, he'll be 5 this summer.
There's currently no way you can determine that your sulcata is
a female, it's nice to call her that for now, it's very likely
to turn out to be male though. That's why trying to "get a mate"
would be a probable disaster as they will fight severely even
to death. (My tortoise is a large lap baby but will try to kill
anything he imagines is another torotise!) Besides having only
one of each sex (if it were that way) would be very stressful
for the female - it would be better to have 2 or more females
with just one male. Depending on how large your tortoise is now,
I'm assuming he's still small enough to pick up with one hand,
you might want to wait and see what it's truely like keeping such
a strong animal with the demands of overwintering them in warmth
that we tend to need in most of the US.
These animals are fine alone, and loners in the wild. I hope I've
given you some info to consider before purchasing another one.
As to the lighting, they need plenty of good UV lighting which
is best provided by a mercury balast bulb (bulb costs about
$50.00 generally, no pet store $8 is going to work - this is
essential for their shell development. There are several companies
that make these bulbs, in a 250 gallon tank you could easily use
a 250 watt bulb or 160 if you added additional heating lamps only.
Make sure to provide plenty of calcium in the form of cuttlebone
(made for birds) and a large variety of greens (endive, escarole,
collards, turnip greens, mustard greens, green peppers, squashes,
zuchinni etc...) and provide timothy hay for opportunity eating.

Theodore my Sulcata tortoise