bandwidth mangement on cisco 4506

hi

iam looking for bandwidth shaping on my cisco 4506.
my data center and desktops are connected to this catalyst and even iam connected to my provider thru ethernet connected to my 4506.

i want to configure acl on all desktop interfaces such that the download speed is 512 kbps from internet but internal speed is full 1 gbps (all servers and desktops are on rj45 gigabit).

can someone suggest a qos policy with acls