as for the beeps can't say mate sorry.

as for the fob its self yes you can replace it with the newer type (ive got one on my fiesta mk4) and the boot poper will work with it, buy a new shell and blade off ebay for a £10 and go to the scrap yard and buy a second hand one (you need the board out of it) then remove the board and bin the rest of it then pull your key apart and remove the chip then place the board and chip into the new shell then fit the blade the get the blade cut (cost me a £5) and then the car will start with the new key then all you need to do is code you board to the car, Which i cant rember how to do lol but its not hard just stick it in the ingtion and push buttons on the key ect i cant rember but someone will be able to tell you 100% how to code them.