Looks like you bought the right UVB> Now this should sit on the screen top and you want a distance of 8-9 inches down to her closest branches. This is important for correct UVI>
Go to home depot or lowes and see if they have some of the Veiled tested plants you can buy. They have a lot this time of year in the indoor nursery.
Start reading this it will help you a lot and ask questions here.
https://chameleonacademy.com/chameleon-husbandry-program-getting-started-with-chameleons/
Plastic solo cup and poke tiny sewing needle size holes in the bottom. Get ice cubes and fill it up put on the top screen away from the light fixtures so it will be above plants so it will slow drip onto the plants. This will trigger a drinking response.
NOTE with her being so small and sick. I would not go up to a 2x2x4ft enclosure right now. I do not know what size you bought but it will be easier to control her environment with a small set up right now. Less space for her to try to navigate especially with her closing the eyes.