Not quite sure I'm following you here. A system image taken from a HDD cannot be used with an SSD. Different ways of storing the data. If you're trying to install an SSD and transfer your O.S. to it you can buy "bundles" that include the hardware and software needed to do that with the SSD. Or you could do it yourself and save some money.
Yes , you can install the O.S. from a usb stick too. If all you're wanting is a working optical drive (external) then almost any of them will work. If you're wanting to replace the optical drive INTERNALLY then my advice is to bite the bullet and get it from Asus. Any 3rd party internal optical drive will NOT look right because of the bezel. (you'll have a big gaping hole in the side of your machine)
If you need help in transferring the O.S. from the HDD to the SSD see this :
http://www.sevenforums.com/tutorials/149969-ssd-install-transfer-operating-system.html
G74Sx BBK-8 Crucial M4 128GB.SSD/W.D.500Gb.@7200 HHD 16GB. RAM Stock otherwise.
An End,even with Terror is better than Terror without End. F.Nietzsche