Its hard to recommend you something when you don't tell us what you are going to be using it for and what your setup is. Do you already have converters and/or pre's with ADAT or S/Pdif? If not your going to be limited by the 9632 since it only has 1 analog I/O, if i'm not mistaken. Since you have a mobile pre i'm going to assume you don't.
I would suggest looking for a used Multiface. Even if you get the first version, you still get 8 analog I/O of rme conversion which would get you started properly to do some serious recording. That is if you absolutely need to go the PCI route and you have some pre's. PCI is definitely the best way to go, i am not saying otherwise, however you seem to be concerned price wise and want to upgrade from your mobile pre to something decent. I would much rather recommend you a firewire interface like the Focusrite Saffire Pro 40, especially since you can get it online for about 375$ and you get 8 preamps along with the same connectivity the 9632 would offer. Remember the RME's don't have pre's built-in like your mobile pre does unless you go with the firefaces.