You do not mention the format of the camera (4x5, 5x7...etc.). I infer from the lens that it could be a 3 1/4" x 5 1/2" format. If you have the film holder then you can find the film at several specialized places, or you can cut it from larger sheet.

You can certainly change the lens/shutter. The lens' focal length should be wide if planning to shoot architecture. For a 4x5 that would be a 90mm or shorter, depending on how tight your bellows compress. You cannot use a lens with a focal length shorter than your bellows compress (a recessed lens board helps a bit there). There are several places to find good used lens/shutter combos. From the big auction place to retailers I am not sure I can mention here, but which you can find if you search the web. You will need to make your own lensboards for the new lenses, and you may still use the original lens/shutter: LF cameras all have interchangeable lenses - you change the shutter and the lens by changing the lensboard, each lensboard with a different lens/shutter!

I recommend you read up so you can find out about movements, bellows factor, lens types, etc. There are several books that will cover this, plus very good inforrmation here and in other websites dedicated to LF photography.