Directory Link Building - I plan on changing my niche halfway. Should I?

Here is the scenario.

I have a site www.ihaveasite.com which currently focuses on internship related content only. I go about link building for a few months and get to page 1 for a certain set of keywords. I have registered my site on various directories for this particular niche (internships). Now I decide I want to also include food discounts, off campus housing and other services/niches that a student might be interested in.

Here is my question --- Is this a problem? If yes, then how do I tackle this problem?

Thanks.

Go ahead and aim for your new kw. Make a new page and deeplink.

But I was under the impression that Google loves sites with "similar" content. So if I dilute my content pool -- from strictly internships & job related content ---to --- internships, housing, food, books, etc. will Google not punish my PR?

Also, originally, my entire site looked, smelt and felt of internships. Now I will change the layout, add more tabs, change the landing page completely, etc. Will that have an adverse effect on my PR?

I'm new to this.

Thanks.

sorry guys. still need some clarity with this one. if nothing else, can anyone shed some light on whether i'm asking a wrong or an obvious question?