none of us here needs to know what your old or new email addy is. We dont have anything to do with any specific network. How or if you can change it depends on the network, but when you are connected, try typing /nickserv help set email If that doesnt work, check the networks website or ask in one of their help channels
Changing it may involve a two step process, like doing /nickserv set email nickpass emailaddress
later followed by a confirmation email with an auth code.
And yes, def update the network with your current email addy since that would be what they would use if you had to request your password be sent to you.