Hi Squeak....You have started by getting your van done but I hope you do not think that "that's it" sign writing a van is all well and good but I think you will need to put a little more thought into your future advertising promotions.
What else do you have in mind to get back those customers?
As the autumn is kicking in I am now starting to really push for new customers and am aiming at each and every street I have customers....I would love to get a new customer on each street.
I have targets set (in pencil

) until 2010....
I would look at those customers that were lost as a godsend (after I had got over the initial shock) and a wake-up call to get out and replace them with some better paid work....
You sound like a smart guy and now you have your shiney new van and soon to be sign-written van....put aside x amount of hours per week to pull in new money...or I know you love your photography...why not decide on buying that next special camera, lense, graphics tablet,, lighting rig and get enough accounts to pay for it (put the tax money aside

).
There are 40 normal work hours in the week....why not use them to make more money....
But anyone who thinks getting a van sign written will get them floods of work by itself is sadly deluded in my eyes (not saying you).
Unless you have tangible targets how can you expect to make progress...all targets should be reviewed on a regular basis to see if they are working and if not why not.
Good luck and I wish you well.