Steve speaks the truth!! Follow his link to "Retail Banks vs. Mortgage Broker/Bankers". Definitely get pre-approved by a mortgage banker/direct lender as well before moving forward. Lately I've had multiple deals come to me after a retail bank across the street repeatedly dropped the ball for ridiculous reasons and delayed escrow for over 2 months. You don't want to be in a situation where you risk your deposit not to mention all the emotional stress Have a plan B. These days I ask for everything up front before issuing a pre-approval letter so that no one wastes their time including you!
Let me know if you'd like for me to take a look at your file.