There is some variety in local codes related to garage conversions, so before you get too much further, see what you're up against there. If you do convert the garage are you going to want to build another one next to it or in front of it for the car? If so, another code question as to how close you can get to the lot line.

To answer your question about putting in a window where the door is, all windows are really custom because they have to fit a specific opening size which isn't the same from house to house or even sometimes in the same house. So there are multiple configurations you could get, but it won't be cheap. Do something in the same style and scale as the other windows on the front of your house or else it will scream garage conversion. If you want specific advice you need to post a picture of the front of your house.

Unfortunately, either you or the previous owner that converted the carport to an enclosed garage with the 2 overhead doors has negated the use of the existing kitchen window. If the overhead doors remain to allow a car to enter, then the kitchen window should be removed to conform to code and life safety.

Get a local competent architect to assist you in your project soon.

It was the previous owners. ill get some photos of the front of the house.

Here is the front of the garage and the front of the house.

In the meantime too, any ideas to make it look better looking into the exisiting garage (obviously apart from cleaning up the space?)

Windows into garages are prohibited by code, so you can start by walling up the window, so as to not have the view into the garage.

Windows in a garage to the exterior is allowed. Windows between the garage and the living space of the house is not allowed unless certain criteria is met. If the garage is converted into living space and no longer used as a garage, windows from one living space to another living space is allowed.

IMo you need to decide what you need , a garage or living space . I do agree what ever you decide you will need to get some pro help to make sure what you do is up to code and the right choice for you. From looking at the layout the eaasy soution would be to close off that window and use the gaarage as a gym but I jave no idea where you live so heating the garage might be a must. I think that space would be a great one for a nice family room if converted to living space but we need to know a bit more about what you need.