You don't install an agent handler from the working ePO server.
Detailed instructions are in the ePO 450 Install Guide, but in essence you find the AgentHandler folder in the extracted ePO 4.5 installation files, copy it to your target machine and run the setup.exe from there.
An agent hander is *not* the same as a distributed repository (A superagent repository is just one kind of distributed repository).
Agent handlers contact the Sql database for ePO regularly, so a very good connection to the host Sql server is essential.
Think of an agent Handler as 'impersonating' the ePO server for clients where it would otherwise be difficult for them to communicate to the ePO server.
To those client it really looks like the ePO server. It serves policies and tasks as well as cacheing updates and events.
An Agent Handler does not maintain a repository though, it only caches files from the ePO server on request.
Superagent configuration is made through the McAfee Agent policy.
There is a tickbox for 'Convert Agents to Superagents' and 'Use systems running SuperAgents as distributed repositories'
Since it is a policy configuartion please be careful you don't accidentally apply it to all your machines