How was it that you got hired again...?
Is your employer providing gear, or do you have to use your own?
Is there a budget for new gear?
At least read the whole thread =)
I did, and my questions are still unanswered. I take it that the budget (if any) for new gear will be very small...
You need to make it very clear to them that you are a web designer, not a photographer. After that (if you still have a job...), if they still want you to act as corporate photographer, well - they need to either shell out for some gear or deal with what you can provide (getting fired is another very real possibility here...). (And possibly send you somewhere to get some training.)
I understand that you are being asked to do a job you were not hired for ... and that sucks.
Welcome to Corporate America... Do things that are not on your resume, under budget, and ahead of schedule. That, or stand in the unemployment line. You don't have to tell me how bad it sucks - I know. You have two options here - get good at photography real quick, or spend every minute you can updating your resume...