#1
forgive if this question has been asked already. i want to know if there is a device that could be place on my acoustic so i could plug in a cable and record it straight to my computer.
plz tell me if this is possible and what i need to buy
#2
If you just want to record it, buy a microphone and a usb-interface (such as the one that is included in guitarrig, which is nice, as it has two 2 inputs for guitar/bass and one for a mic.
otherwise you can install a pickup. Keywords: "Pickup acoustic"
A piezo could sound great.
But usually to install a pickup you have to drill a hole into your guitar's body.

http://windworld.com/products-page/electronic-hardware/sdt1-piezo-film-contact-pickup/
Actually this could be what you are looking for!
#3
No problem at all. You can buy magnetic soundhole pickups, internal mics, contact transducers, or better still, a cheap USB condenser mic like the Samson C0-1U.