Efficiently Updating Address List for Non-Profit Organization: Any Suggestions?

[Flyer]

So my summer job consists of me updating a list of addresses. There are about 11,000 entries from 3 to 40 years old. It's for a non-profit organization, so it kind of has to be cheap. Anyone know where I can go or what I can do? Oh, and I have birthdays too. Does anyone have any ideas?
Note: this is a completely legit organization. The people on this list willingly gave us their names and addresses.

 

[mapper]

Is the data in a database already or do you have 11,000 paper entries? What needs to be updated and why? I could write the sql if you need it, just need more info.

 

[Flyer]

The data is on an Excel spreadsheet (which was created in 2002 from 11,000 index cards) and run through the National Change of Address. They only record the changes of address for the past 4 years. What I need to update are the addresses and possibly (but I hope I won't have to) whether or not the person is still alive. I was wondering if anyone knew of any websites/services that can do this en mass. I don't want to scan them all through whitepages.com. The reason: we want to get in touch with them for our organization's anniversary.