(a) Execute purchase orders for the purchase of citywide computer hardware, software and peripherals with E&A and 21 Tech, doing business as a joint venture called Xtech, CDW-G and ComputerLand in an amount not to exceed $500,000 each and to amend the amounts of the purchase orders during the term within the collective amount of $1.5 million, for the period, for the period of July 1, 2006 through June 30, 2007; and