Having Countrywide carrying the loan with you should help you even more.
Under normal circumstances. . .the listing agent should be able to tell you exactly how long. . jusk ask them before you put an offer.
If this a Bank Owned... you could be competing with multiple buyers. Bank Owned homes are answered quickly than short sales. Just make sure you send them all of your paperwork along...pre-approval, a copy of check stating the deposit amount, bank statement showing the money is there, contact information of your banks and lenders...you want to show them that you are a serious buyer...and your offer is backed with constructive reasons...local market comps, similar sold units...if the property does need some work...make sure send a copy of estimates...and ask for the shortest escrow time.
Keep in mind, the have thousands of homes to consolidate...one fax error, one typo can put you behind the rest of constructive offers.
And one last thing. Buying a home is not about luck...it's all about executing wisely.