Broken Exhaust Resonator?

[brandonmpace]

My exhaust started making a funny sound a few weeks ago. I thought it was coming from inside my muffler, but I was wrong.
Today I started it up and noticed it was louder than normal.
As I took off I noticed that it sounded a lot like a 4-stroke dirt bike with a nice exhaust, but with a crappy sounding rattle.
While sitting in the car I leaned over and down to see under the car and pushed the gas a little. It is coming from what I assume is the resonator. It's the canister between the cat and the muffler.

Where is the best place to get this fixed? I've been out of a job for two months now so I also have to be cost-conscious.

Since it started making noise I've been getting about 4 more MPG than normal, and I'm afraid getting it fixed will bring this back down.
Does a higher flow exhaust also give better gas mileage? Because this appears to be all welded in, is it better to replace/upgrade the midpipe and cat as well?

Pics to show exactly what I'm talking about.. I'll get a closer look tomorrow myself as I took these pics when it was dark.

[black roadster]

Take it to Pronto Muffler. They are on the northbound 75 service road just north of 15th Street. They are fair in their prices and a good shop. It might just need to be welded to be fixed. I can't tell from your photos what the problem is.

[brandonmpace]

Upon closer inspection in the daylight I found out my resonator seperated from the pipe at the weld. The third pic shows this, but it's not obvious.
Got it welded back for cheap, but they warned me that if something caused stress in that area it may happen again. I haven't hit it on any bumps, etc, so I guess we'll see.
Thanks for the advice!