Also be aware that Vista usually comes locked down pretty good. You might want to go into the Networking and Sharing Center and make sure that network discovery is turned on. That might make it a little easier for you.
If I am understanding correctly, the Drobo and the Printer are both being shared out by the a single computer, or are they directly attached on your network?
To find your subnet, you can do the ipconfig / all and scroll up in the dos window to look for your network adapter and see the settings. You can also go into the Network and Sharing Center and choose Manage Network Connections to view each network adapter (both wired and wireless) to take a look at their properties (via right click). I believe you right click the adapter, click properties then scroll down to IPV4 and click properties on that.
I have also seen Vista machines that did not have the Client for Microsoft Networks checked off - which it needs to be since your Mac will be sharing to windows by looking like another Windows machine.
Once it look like you are all good. You can go back to the command prompt (where you typed ipconfig /all) and try to type ping, followed by the addresses of the machines you are trying to connect to.
Once you are sure you can connect you can try to connect the drives by using Tools - Map Network Drive when you double click My Computer, or if you have your computer icon on your desktop, you can just right click on it and select Map Network Drive.
To setup your printer, there is a wizard for adding a printer. I am using a 'classic' style menu so for me it is Start - Settings - Printers, but you can always find it under the control panel. Click printers, then add a printer and select add a network printer.
One last, thought. On my vista machine I have bonjour installed (which is for network discovery). I think it was installed when I installed iTunes. So if you don't have it on your machine, you might want to try installing iTunes and see if it automatically installs Bonjour, which should make it easier for your to find all devices connected to your network.