You can try going to Realtek and looking for new drivers
But don't get your hopes up.
This forum has many posts from people who can't get "what you hear" going on Windows 7. Sometimes, you can get it going with Vista drivers in compatibility mode. Sometimes you can find a hacked driver
. Sometimes you can struggle on your own for 20 hours and eventually stumble into a working solution.
Sometimes you will fail.
It appears to be a deliberate bit of cooperation between Microsoft and sound vendors to foil attempts at recording "what you hear"--probably out of copyright concerns.
Your ultimate alternative: buy another sound card that is KNOWN not to have this limitation in Windows 7. There are a few out there. That might be a problem with a laptop. Maybe an external USB sound card might work for you?
In the meantime, pound this forum for "Realtek" as a search term and you might find a solution. I have both Creative Labs (standalone card) and IDT/Sigmatel (onboard sound) and eventually got the onboard sound to provide "what you hear" capability---but I pulled out a lot of my hair in the process.