Do you mean display it next to your nick, or actually get the operator / voice status?
You cant just "get" a +/@ in front of your nickname. + refers to voice status and @ refers to operator status-- both of these have to be given to you by someone with operator status (@). In most cases they have to be *earned*.
Operators (@) are analogous to the administrators/owners of the channel. You can't just say "I need to be an owner of this channel" and expect it to happen. Usually such a request results in your removal from the channel.
As far as the + voice status goes, it's mostly symbolic unless the channel is +m. Voice users have no power besides the ability to talk when the channel is +m-- so if the channel is not +m, there's no reason to even ask for such a status unless you're the kind of person who likes looking at yourself in the mirror with expensive clothes on.
If you "can't do anything" without those statuses, there's a good reason for that.. you shouldnt be 'doing' anything besides chatting, on IRC. Administrators have the extra responsibility of maintaining channel order, but I wouldn't consider it something "to do". If you want these statuses, join/create your *own* channel where you have this power.
You can learn more about modes and how irc works by typing /ircintro in mIRC and reading about it.