I don't know what your current onboard sound chipset is, but your Novatech CMI (C-Media) 8738 is the PCI version/equivalent of C-Media's (excellent) onboard sound chipset offering.
This chipset and the even better 9738 followup offer remarkable value for money and the PCI versions have been available for some time from around £4 to £6 upwards.
I used the 8738 onboard sound for four years until I was given a SoundBlaster Live! and there wasn't all that much in it in the end, with the Live! producing a somewhat more solid overall sound via my IBM 2.1 system; however the C-Media's clean, transparent sound quality was remarkable, along with its 3D capabilities.
Here's C-Media's website for drivers etc:
If your computer system is suitably cabled, you may not need to connect the CD/DVD drives directly to the card.