Here is a list of quakenet servers:http://staff.quakenet.org/servers.phtml
to change a server manually, use the following example as a guide:
In the status screen, type the command on the typing line:
/server<---(this is the server command)
jubiigames.dk.quakenet.org <---(this is a typical server address)
The command should look like:
/server jubiigames.dk.quakenet.org 6667
The numbers 6667 are just a port. Typically, you should include the port in the server request. 6667 is a common port used by mIRC.
If one server does not connect well, try another. Remember, sometimes servers have ALOT of traffic on them. This is the reason why some connect better than others. Also, a server may be down for maintenance. So, just keep trying different servers untill you find one that connect for you well. Make sure you make note of that server so you can use it again.