Canon EF 50mm f/1.8 II - Good for indoor and lowlight?

the 50mm f/1.8 is very inexpensive and peforms very well in low-light compared to your current lenses ... it is currently $94 at bhphoto.com
50mm f/1.8 at canon price watch

if you can stretch your budget a little more, the well-regarded sigma 30mm f/1.4 is being discontinued soon and is very well priced at $284 at buydig.com (down from over $400)
30mm f/1.4 at canon price watch

a few things to consider:

• set your current lens to 50mm and see if that focal length suits you, you cannot zoom with the 50mm and you may find that you don't have enough room to frame your shots
• 30mm is a very good focal length for smaller cameras such as yours ... set your lens to 30mm and see for yourself ...
  
• the 50mm will fit on almost any canon camera, but the 30mm will only work well on smaller canon cameras (7d, xxd, xxxd, xxxxd, and rebels)

hope this helps ...