I looked thru your link, and it appears to me that they are using a fairly simple MS Access Database. The "Base" Program in OpenOffice is not really up to that standard yet, but they are working on it.
There really is nothing being done there that could not be maintained in Spreadsheets. Check out this page.
I only wish I had the capacity to do it myself - sigh!
You might be surprised what you can do yourself over a period of time ... even a few years. Keeping well-organized spreadsheet info around, while slowly learning how to set up a simple database (which becomes part of the kids's curriculum, if (or, as soon as) they're old enough, would be in interesting project. Feel free to leave hubby out of it, unless, of course, he insists on partaking in the fun.