Other than the onboard sound on yours, everything else is good to go looking at the full specs here, Gateway Support - Specifications
Not much Gateway or you can do though when the company that made the audio chip (and drivers
for it) is basically out of business.
In your case a cheap sound card or USB headset that does have Windows 7 support will have everything up and running. If you go the sound card route stick to something from Creative/ Auzentech/HT Omega/Asus. If you go the USB headphone route going to have to wait for a recommendation on that as I have no idea what to recommend.