First, 48Khz isn't going to give you any more. 16 bit/44.1Khz is "CD Quality". 48 Khz is usually only used by recording studios that are developing audio for Video use so it will sync properly. I have a recording studio and only use 24 bit 44.1Khz for the majority of my recording (and mix down to 16 bit 44.1Khz for the final product).
The PNY site doesn't list what the HDMI audio specs are for this card.