Load Balancing with one Internet Connection!!!!!

Hey,
I am using 512 Kbps Internet connection in my PC. I want to share it equally for Browsing and Download. Just like, If I download a file, it will be take 256 Kbps from 512 Kbps and if I browse from any browser it will be take 256 Kbps from 512 Kbps.
Is there any way to do this job?
Thank You…
