Hi ashess! Good Job!!
When I started trying to make humans I did it the same way you are doing it. Hehe, it took me a long time to discover that that was not the best way to do it…
Now, my advice is that you stop rigging that model, and you start ¨retopologizing¨ it. So, a good thing to do would be that you add some multires levels to the model, and that you sculpt her just as you want her to be in High Resolution. When you have finished, make a new object, go to edit mode, click on the retopo tool and start drwawing the geometry from scratch.
Here are two videos showing up how to use retopo:
You shoud take a look at a good human topology example model like this one:
Download the .OBJ models at subdivion levels 1 and 2, import them in Blender and try to reproduce that kind of topology in your own model with the retopo tool.
If you work with all these in mind you will have the best starting point ever.
For the rigging part, my reccomendation is that you don´t use weight painting. Use the Mesh Deform modifier aproach instead. You can have a look at the Big Buck Bunny characters for that. You can also check out my project, it is called BlenRig, and it is a human characters rigging system. With my aproach you won´t need any shapekeys in your model, and you will be able to achieve the best deformation possible.
If you wanna use the shapekeys aproach, check BenDansie´s character at this thread:
Well, you can download BlenRig at www.jpbouza.com.ar
Here is BlenRig´s Vimeo channel for tutorials on it.
Keep it up!!