Sorry I didn't reply to this sooner, Never, I wasn't on for the last couple of days. Anyway, esaym is right, those are probes. If the probes found a port open, then it might try to use it to load one of those bad things onto your 'puter.
You can look up IP addresses by opening a command window (Start->All Programs->Accessories->Command Prompt, or simply Start->Run... and enter "cmd"). At the prompt, type "nslookup" followed by a space and the IP address. However, it may not tell you much useful, especially if the attacking computer is also assigned an address at start up.
Yes, the numbers after the IP are the ports. Ports are usually associated with specific services, so you'll typically see attackers probing the same set of ports, where there might be a compromised service. Sometimes they try multiple ports, sometimes they attack the same port multiple times in slightly different ways.
Keep your IP address secret is a very weak form of security, right up there with keep your SSN secret: the cat's probably already out of the bag anyway, and besides, they may just be randomly guessing IP addresses.
Keep that firewall up, that's your best defense. Check and make sure that you don't have any exceptions in your firewall that you aren't aware of. Also, be sure to apply updates regularly.