Sorry George, but what you are asking for doesn't exist.
Here are some things to look at to get started on a budget:
What are your fixed costs? salaries for IT department, maintenance contracts, Internet connection costs, outsourced operations, etc.
What are your known variable costs? travel to remote sites, conferences, emergency repairs, etc.
Are there any know growth/expansion plans? need for more equipment, increased staff, infrastructure for additional sites, etc.
What isyour equipment lifecycle plan (usually tied to your company's capital amortization plan)? Create a plan such that as a computer's amortized value reaches 0, it is replaced with newer equipment (not necessarily the latest, "bleeding edge" model, butstout enough to last until it is time to replace it again). Such plans usually count on replacing a certain percentage of equipment per year.
Hope this gives you some things to think about.