Well, you stand a pretty good chance of getting the job since you already work for the company. Make sure your current work is top notch, and that you're in good standing with your current supervisor.
If your bosses already know that you're a fast learner and good with problem solving, those skills are more valuable than damn near any cert you could get. Those are the kind of skills that are complemented with certs, not made with.
I've looked through many IT job postings myself and I never really see anyone asking specifically for an MCITP. This could be because there are different "flavors" of that particular cert.
http://www.microsoft.com/learning/mcp/m ... t.mspx#EMB
Figure out which one you want to go with, and start from there.
The first thing I'd do is get a good book on Server2008. If you've worked with 2003, there'll be some changes, but you'll already have a grasp on most of the technologies. Most of the MS stuff is common knowledge for an IT guy. ActiveDirectory is MS's version of LDAP, which is part of the TCP/IP protocol stack. Exchange I'm sure has some Exchange-only quirks but deep down, it's just an email server. If you know these underlying technologies, learning the MS apps for them shouldn't be a big issue.
The Microsoft books are stuffed full of good info, but they all seem to written by C3PO or Data. They're very dry, but this is a common trait of tech books from the manufacturers. They're good for reference books, but for something you sit down and read, they're as dry as the Mojave.
http://www.amazon.com/s/qid=1239872407/ ... 2Cn%3A3771
I've used the Sam's Teach Yourself _______ in 24 Hours books, as well as a couple Windows Server books by Mark Minasi. The Sam's books I used for Networking and were pretty good, but I give the best recommendation of the two to Mark Minasi. I have the Mastering Windows Server 2003, and it's easy to read but doesn't seem to skimp on good info.
I haven't used Windows Server products myself, and I understand your plight. It's like trying to become a Porsche Certified Technician at home on a middle class budget (read, it can't be done). If the job really means something to you, the initial cost might be high, but there's nothing better than getting your own copy to play with. Also, you can download trial copies legally from Microsoft IIRC. If you're a student, I've been told you can get a pretty nice discount on Microsoft stuff like this, but I can't speak first-hand for this.