You definitely need at least one real plant. They help with humidity and your chameleon will be very unhappy without one. If you need a list of chameleon plants, here is a good one:
https://flchams.com/chameleon-safe-plant-list/
For basking temp, shoot for around 80-85. That will be best for the chameleon.
As for the egg process, if you just recently bought her from PetSmart, then I am guessing she is under 5 months old and therefore not sexually mature yet, which you may start to notice maturity around 6-7 months, but every chameleon is different. Do you feed her every day?
Also, you are going to need to find calcium without D3 soon because you shouldn't give them D3 calcium at every feeding. You should have a cycle between regular calcium and D3 calcium. Usually the calcium product will advertise the fact whether it has D3 or not.
Also, handling once a day may be a bit to stressful for your cham. Limit it to maybe once a week, if not less often than that.
The dark coloring is probably from stress. Can you send a picture of her entire enclosure so we can see the setup? Also, you may want to think about buying a linear UVB bulb because they are longer lasting and are easier on the chameleon's eyes. Hopefully some of that helps.