Definately get the turtle some outdoor time - even a few short trips a week outside so she can walk around would be great. Just make sure the grass hasn't been treated with anything.
There's a lot of great information on this forum (as was already pointed out), and if you want to see enclosure pictures - go through and check the threads that had "Image" next to them. Everyone has been showing off their enclosures lately 
There's been past threads about what to do to help get picky turtles to eat - with them, color and smell is a great motivator. So is being hungry, don't give in and feed insects every time or else the turtle will know she can get what she wants.
If you intend to keep her inside you may want to try getting a very large solid colored rubbermaid tub. These have opaque sides and are less stressing to turtles. Or you can try building her an indoor enclosure, such as a turtle table http://www.unc.edu/~dtkirkpa/stuff/table.html.
General rule is 4'x4' minimum for one turtle - though that's honestly not that large once you start adding dishes and hide spots. For the time being, covering the outsides of the cage you have with some paper would even help. She also looks a bit dry, so a better substrate such as a mix of peat moss and sterile top soil would help hold the humidity she needs. You can (and it looks like you really should) also take her out for daily soaks.
As for bad plants - http://www.chelonia.org/Articles/plantsthatpoison.htm
Can you take some better pictures of her in natural or brighter lighting? Get a good side view of her face if you can and a picture of her feet. I'm guessing that she may need her claws and/or beak trimmed.