Not to sound harsh, but it seems like you've simply got the wrong tool for the job. You are using a somewhat dated, middle of the road, consumer dSLR camera for income you depend on in a cutthroat market. If the tool you are using is losing you income, then you simply need to invest in a tool that can perform the job you need it to. Right?
Aside from that, your picture, as others have stated, is certainly in a suboptimal environment and underexposed to exacerbate the noise that becomes present in these situations, no matter what the crop body. You can see others' examples here from similar and lesser (40D) crop bodies with better lighting and higher ISO's with less noise than your photo. These crop bodies just really need great light. I remember how disappointed I was with my 7D's noise in a lot of photos when I first got it, until I learned how to shoot to the right and find the balance of PP tweaks.
It really is unfortunate that you can't touch the photos before sending them off. I own both bodies and the 50D and 7D are prime examples of crop bodies that really benefit (and often require) from sharpness and NR adjustments in PP.