You need at least Adobe Camera Raw (ACR) 7.1. For that you need CS6, or else use the DNG converter, latest version 8.2
CS6 requires a new computer, will the DNG converter load on to CS4? My computer is operating with a Motorola chip, a bit archaic, but can it use DNG 8.2?
The DNG converter is a standalone application, separate from and independent of Photoshop/ACR/LR.
It converts your D800 NEFs to the universal DNG format, which can be opened by an older ACR/LR version that doesn't have native support for the camera. DNG is still raw, and there's no data loss.
That said, your D800 is a fantastic camera that really deserves the new raw conversion engine from ACR 7/LR 4 and onwards (process version 2012). The improvement is dramatic, especially in highlights and overall dynamic range. Compare the results for yourself to what's possible with Lr 5 on your wife's MBP. Yes, I know, it's a never-ending race to upgrade this, then that...it never stops