Lumix 20mm f1.7 for my existing EPL-1 or buy a new EPL-3 for the same price?

Hi there -

I'm going to apologize in advance for my lack of knowledge, as I'm pretty new to the whole world of Micro 4/3 and for that matter, photography in general.

I bought an EPL-1 a year ago which came with a 14-42mm kit lens and a zoom lens (M.Zuiko ED 14-150mm f/4-5.6). The main reason for buying this camera was to take pictures of my very active 5 year old boy indoors, and sadly the kit lens isn't very good.

After doing a bit of research I saw that the Panasonic 20mm f1.7 lens would be a good choice for low light photos, so I'm strongly considering that. However, at $350 for the lens, I'm wondering if i should just spend an extra $100 and buy a new m4/3 camera, since there are m4/3 cameras around that price range (such as the EPL-3 or the Lumix Gf5).

I'm not familiar with whether these m4/3 cameras I mention come with a better kit lens than the EPL-1 kit lens (which isn't working for me).

Any thoughts on this would be much appreciated! Am i just better off using the 20mm f/1.7 on the EPL-1, or just buy a new m4/3. I would ideally like to keep within my budget of $400-$450.

Thanks!