With existing structures it is best to seek a talented local architect that will be able to gather all the existing information and conditions that will effect the design.

I would want to match the windows and unify the style ... you have traditional windows surrounded by more modern looking windows.

Is this the view people see when they pull up to your house? If it is, then I would plan on spending a lot more on a garage door that is nicer looking than a basic garage door.

I'd remove the mullions from the two middle windows, and paint your garage door the same brown color as your siding.

The two center windows look like French doors making me wonder where the raised deck disappeared to. So, I would change them to match the side windows to eliminate that appearance of a project needing to be completed. As for changing the garage door color or style, a view of the entire front of house is needed for anyone to make realistic suggestions. Will you post a pic taken from farther back?