I need to get a new front deraileur and I like to try to do this kind of thing myself because its fun, so please excuse my ignorance.

I'm not clear on what kind of front deraileur I need. Right now I have a bottom pull, top swing fder. Does this mean that I have to go with a top swing new fder?

Also, I'm not sure what the capacity figures mean on the shimano website in regard to front deraileurs. Right now I have a double chainring in front that is 34-48. My cassette on the back is a 34-12 I believe. Does this affect what kind of front deraileur I need to buy? Since I have double cranks in front, rather than a triple, can I use an mtb front deraileur that is made for a triple chainring setup?

Thanks so much for any help with this.