Hey,
First of all, i like the greyish colour, on your navigation background.
It certainly looks better then the bright yellow and oranges, so with that in mind, try and replace the yellows or oranges with the greyish colour, however, don't replace both, you don't want to loose all colour and have it looking flat.
Try and add some CSS, to the link colours, the standard blue links really don't look too good on any site, they are too bright and saturated, and certainly don't match your design.
Re save your header image, the shadow on it has gone pixelated, if it is still pixelated, save it with a white background.
Your welcome paragraph, give it a header, make it standout, draw people's attention to it.
Basically, make more use of colours, don't use such bright colours, and do general "re-touching".
Good luck.
Adrian
