$1 trillion doesn't even cover it. Most all experts agree at a minimum the war will cost around $2.5 trillion to as high as $3.5 trillion. Once Congress passes the funding for the war to last until spring of next year our hard costs will be about $750 billion just on the military effort. But one also has to add in the other costs that must be borne, including but not limited to:
The additional interest on the debt incurred financing the war.
Paying for healthcare and making disability payments for the next 30 to 50 years for all 31,000 wounded (so far) in the war.
Additional veteran's benefits war time action merits.
Replacing weapons systems prematurely worn out and lost in combat.
Death and survivor benefits payment for those killed in action for all of their family and children
And the list goes on and on. This author wrote a book about it, called 'The $3 Trillion War'.
http://www.vanityfair.com/politics/features/2008/04/stiglitz200804