That is not sufficient, unfortunately. A T5 tube is best in the long run, but if you can find a 26w Exo Terra UVB200 that will fit in your existing fixture and work better than what you have now.
Yes --- I can attest to the performance of 26W UVB200 globes. I've been using these for years and have had good results. NO MBD in any of my dragons or skinks. The dragon needs to be able bask inside 8 inches from a 26W UVB200 in a hood or dome.
Getting her in the sun will give her an immediate strong dose of uvb. Not in a glass tank, tough. Just set her on the grass/dirt. Glass tank would heat up + kill her.
By the way, do you have a heat bulb besides the uvb bulb ? I didn't notice it listed when you gave a rundown of your tank. If not, you desperately also need to get one right away.
So what I do is that I control her heat with the sun. I know it doesn't give uvb rays but it's just fo the heat. It doesn't heat up a lot. I also have a thermometer to check her temp.
You will need a good bright white basking light also, such as a PAR 38 halogen that you can find
at Lowe's or Home Depot or maybe even Tractor Supply. The brightness along with the UVB is a
great combination. If she isn't warm enough, he wont be able to digest properly.
The eyes do need some brightness in the tank to help alleviate stress & strain from UVB rays, too.
Their behaviour is strongly dictated by their environment.
The sun is great if you tale them outside to sit in the grass or if you have a cage outside, with part shade of course. But do you mean that the sun comes through the window to heat the tank ? If so, that won't work because it will heat the entire tank with no way to get in a cool area. And the uvb does not go through glass. If that's not what you meant then I apologize.