Hi Philip,
IP addresses actually have 12 numbers - xxx.xxx.xxx.xxx - but they tend to drop leading zeros so it can sometimes fool you. The following may help: http://en.wikipedia.org/wiki/IP_address and/or http://computer.howstuffworks.com/internet/basics/question549.htm.
To confirm your own address, go to Start / All Programs / Accessories / right click on Command Prompt and click run as Administrator. Then type IPCONFIG /ALL and enter. It will tell you your IP address and much more about your connections. Remember, unless you are using a static IP address with your ISP (typically very unlikely), then you have a dynamically assigned address which means it could be different every time you login or remain the same for some ISP-determined period of time but eventually change even then. So the IP address from your ISP is sort of a moving target and tying someone to it requires knowing both the address and the time it was being used (and cooperation from the ISP for that address to provide further details which I imagine will be hard to get without a court order or something like that).
You can find information about the owner of an IP address (maybe not the specific address but more likely the range of addresses which includes that specific address) using WHOIS. Here's one place that offers that: http://tools.whois.net/whoisbyip/. Here's another option: http://www.whois.sc/. You can find others by just searching Bing and inputting "whois" as the search term and you'll get more than you can imagine.
To geographically locate an IP address, try the following: http://www.geobytes.com/ipLocator.htm?GetLocation. Here's another option: http://www.ip-adress.com/ip_tracer/. For other alternatives, search Bing for "IP address locator" and you'll again find many options.
If you have an email from the hackers, you can possibly use the following to track them: http://www.ip-adress.com/trace_email/.
Once you know who owns the IP address block or the address itself, you can then contact them to see if you can find out any more about the specific ones you're interested if you also have the exact dates and times that go with them - but I frankly don't think they'll provide you with any information without a court order.
Furthermore, there are programs out there that can be used to mask your IP address or send a false IP address and most hackers use such programs so even if you try to track it down, you may discover they have covered their tracks with multiple false IP addresses (sometimes dozens) from their own real IP address to the one you see in the emails and trying to track that down is daunting even for professionals.
I recommend you check out the following site where the government helps people who have been victims of computer-related crimes:
http://www.ic3.gov/complaint/default.aspx.
I hope this helps or at least gives you a start on your quest. To be honest, the chances of truly finding these people without being a hacker yourself or hiring a hacker are quite slim, but you could get lucky and if you do decide to report it or get help, the more information you can provide,the better the chances they'll have of doing something.
Good luck!