Those older Dell corporate laptops like your D630 were built like tanks, really sturdy stuff.
To my surprise, Dell still offer drivers for that laptop, but only up to Windows Vista. The easiest way to locate the right drivers for your laptop is to use Dell's "Service Tag" number, it's usually on a sticker stuck onto the bottom side of your laptop. Alternatively, you can click the "System Analysis" button and let Dell install a small program that will scan your laptop and come up with the proper drivers, this may work or it might not because you have Windows 7 and not Vista.
As for your PC card, one way to tell if Windows 7 has problems with the PC card hardware is to click on START, go up and right click on COMPUTER and click on MANAGE, this will launch the Computer Management console.
In the left pane of the Computer Management console, find and click on DEVICE MANAGER, all of the hardware on your laptop that has to work with Windows 7 will show up in the middle pane. If Window 7 has a problem with a particular piece of hardware it will either put a yellow question mark next to it - meaning that Windows 7 has detected the device but could not locate and install the correct driver for the hardware, or it will put a yellow triangular symbol with a black exclamation mark next to that item - meaning that Windows 7 is having a problem assigning system resources to the device and/or having driver issues.
But here's the bottom line with older hardware, even if you did get that PC card working it might not be as fast as that USB SD card reader adapter you're already using, I'm assuming that the laptop has USB 2.0 and that you're using that USB 2.0 port.