Convert bdf file to ttf
For converting file types (fonts) from Macs (.dfont) to TrueTypeFont (.ttf) that then can be used with Windows I recommend to use the DfontSplitter.


  Convert Macintosh .dfont files into TTF format


However, converting file type will not add new characters, it will only convert the file type while the characters stay the same.

For Latin fonts the (special characters) and accents are keyboard feature and can be set in the keyboard system preferences.

I you have for example US keyboard and want to use the French accents like èé ÈÉ, set your keyboard to French. 

But if you want to continue to the US keyboard and still need those characters, then use the:

1- Insert function from the (Characters viewer)

2- create a special function "Replace- With" in keyboard menu, then use a word to be replaced with the accent character. (now you just type the word and it will be replaced)

3- or another way is to use this method (while keeping your original keyboard layout:

: To get accented vowels on a Mac, hold down the Option key, and while holding it down, type the letter e; to get (é É) then release those keys and type the letter that you want the accent to appear on:

Press alt and e now release those keys and type the letter you want with accent.

4- Finally if you just hold the key pressed there should be a pop up allowing you to select the right accent for that letter.

So the choice is your what method suits you best.