Upgrade 5770, or CF?

hey there, looking for recomendations on either upgrading or add a second and crossfire my 5770 gpu, reason being is for bf3 not sure if current setup will be enough for high-max settings. computer is currently not overclocked and havent tried it yet, but if needed i will oc. still new to the computer building process this current setup was built in feb. and havent done much to alter performance etc. would adding a second 5770 and running cf be adequte enough instead of buying say the 69xx that is reccomended on for the game. budget well obviously like the rest of us i want the best bang for the buck, but i am not opposed to buying a new better card then what i have now. i would even wait for the new 7000 series of cards to come out if that is a better option, i have mw3 for the ps3 coming to me aswell so i can wait  

thanks in advance

USAGE FROM MOST TO LEAST IMPORTANT:main usage is day to day internet browsing, streaming video to ps3 and gaming

CURRENT GPU AND POWER SUPPLY: his 5770, corsair 600cx

OTHER RELEVANT SYSTEM SPECS: amd 965 black edition, patriot sector 5 "G series" 2 4gb sticks, gigabyte 890gpa-ud3h mobo

PREFERRED WEBSITE(S) FOR PARTS:any reputable site

COUNTRY OF ORIGIN: canada or us, whereever will be cheaper

PARTS PREFERENCES: dont have a preference this is my first video card so something that will work

OVERCLOCKING: Maybe SLI OR CROSSFIRE:Maybe

MONITOR RESOLUTION: 1920x1080