There's nothing wrong with running for weeks or months at a time without shutting down or restarting.
Both are false. It's important to remember than "Genius" is only their job title, and not necessarily an indication of their knowledge, experience or expertise.
Mac OS X manages your memory automatically, and can use all memory that you have available. Also, there's more to the picture than free memory, as inactive memory is also free for apps to use. You don't need to worry about memory unless you have page outs.
If you read the post before yours, you'll see the OP already upgraded to 8GB of RAM.
Viewing all the processes won't necessarily help, since the page outs could have occurred at any time since the last restart, but the high memory utilization may not be occurring at the time of the screen shot. That's why it's better to restart, which resets page outs to zero, then track page outs under normal workload. Certainly, it's possible that a particular app is a memory hog, but catching that in a screen shot isn't assured. Still, I usually recommend using "All Processes" instead of "My Processes" for any Activity Monitor usage.
You may not need to uninstall it. Just delete any occurrences of it from any of the following locations:
It may launch only when you print something. Keep an eye on it and see if it consumes RAM again. If it does, you may have to manually quit it every time you print, or you might be able to uninstall it without negative effects. I'm not sure what that particular process does, or whether it's critical to printing.