I know that soundcard, because my dad had it in one of his older pc's.
If you can upgrade, do!!!
In the time, I've had many different soundcards, and most were even good ones.
In the IT era, I had a Gravis Ultra Sound. Went to a Creative AWE 32 Soundcard, then to a SB Live, SB audigy and I now have an SB X-Fi Elite pro.
Each soundcard is better than the previous, and with each purchase, my songs became alot better. Not just because it sounds nicer, but as bvanoudshoorn points out, by not hearing the sound, you don't hear your mistakes that much either. My XFi now even plays noise if a sample has it, which allows me to seek for good samples, but even tracking using bad samples is better now becaues it just sounds good.
Do note tnat the same applies to speakers. If you upgrade your speakers regulary (say, on a 2 or 3 year bases) you will see how much of a difference this makes. Unless ofcource you already have studio monitors.