Price of a valve job,and how long to do and get my car back

'IF' the valve itself has failed and is the cause of low compression... The only way to get that compression back is valve replacement! .. Strongly suggest getting another option from another shop/mechanic for a closer look at - and more testing of - the 'active fuel management system' *components* before proceeding.. That was just a suggestion.. Whomever is going to do the work should be the one to answer your posted question, don't ya think?