Warning: The following is a "soft" answer. It may not actually be helpful.
I'd mention less, actually. This is a mistake I've made -- trying to fit in as many ideas and examples into a talk as possible. That's often a bad idea, especially when giving a talk to undergraduates. Pick a few ideas you want to develop, even if you won't be able to get to the incompleteness theorems themselves. It will suffice to develop the historical background of the subject, talk about consistency and completeness in logical systems, or go right for the gusto and talk about Godel's incompleteness theorems, but without lingering too much on the technicalities of the proof. That way the audience walks out having learned something concrete rather than getting a whirlwind tour through a subject you spent weeks learning about.
I recommend you make your talk interactive and engage the audience. If you want to introduce Richard's paradox, for example, ask people to propose their own explanations before delving into the distinction between mathematics and meta-mathematics. I think it is mistake (not necessarily your mistake) to think that the speaker needs to always be talking when giving a "talk". This is especially the case for "philosophical" subjects like the incompleteness theorems.