Perfmon and memory utilization

I am using OpManager to monitor my servers. I have 1 server which is performing numerous duties, AD, DNS, DHCP, Print/file serve, SQL, IIS (intranet), veritas, opmanager, i think thats it.

I am running a Dell PowerEdge 2850 with quad 3.2GHz processors and 4G of RAM. This server is showing 62%-89% memory utilization when viewed through opmanager.

I want to see a live view of this, so I thougth of using perfmon. What counters will tell me how much of my memory is being used.?