Upgrading 500D to 50D or 60D

Normally I photograph landscape & environment portraits (outdoors) and group photos & portraits (indoors).

In low light (indoor), I bump up ISO to 800 or 1600 and find result not very good. Will upgrading my camera to 60D give good improvement in ISO performance (Alternatively 50D are available at good discount).

I am looking separately to include a F2.8 zoom in my lens line up. However this post I will keep to camera upgrade only.

Thanks in advance

I find ISO performance on my 50D quite good up until 1600. It's useable at higher ISOs, but with a lot more post. Can't speak for the 60D, im afraid

I don't think 50d is an upgrade from 500d in the image quality department. It is basically the same sensor. Otherwise if you are interested in upgrading, because of the build quality, better handling and extra functions like MF adjustment it is a huge step.
I never used 500d but if you expose correctly you should easy go up to ISO1600.

I went from a 500D to 60D and have not regretted it. The ISO and IQ seems better to me, the AF is better and the body feels so much better in my hands, the rebel bodies feel to small now.

If you want "upgrade" look at the 60D. There's just not that much difference in IQ between the 500D and the 50D, some more features (bells and whistles) but no improvement in resolution.

is 60D IQ equivalent to 7D IQ in terms of ISO performance. From above I am assuming 500D ISO performance is at par with 50D.