switching from the pc's ordinary onboard sound to a simpliest creative sound card is making a huge difference in sound quality. but switching from a lower to a higher model between sound cards do not give enough benefit. i don't know about mobile world but i suggest you to keep this information in your mind.
don't feel yourself bad because you are on this price range, there are very good models around. you just need to select the correct one. if bass is your main concern, i can suggest you to pick something from koss. Vsonic VSD3 series is also good. i have both KDX100 and VSD3 and i can say they are nearly identical, while koss offers a little bit more bass and more recessed treble compared to vsonic. they both sound good. their frequency seperation is very good. you can easily distinguish the bass, treble and vocal sounds in a very big atmosphere.
but they are also "hard to equalize" earphones. they come with a lot of strong bass frequencies (250-500hz especially) amplified which might require a lot of equalizer lowerings to sound true with certain types of sounds, they somewhat hard to use because of that.
i can also recommend brainwavz r1, it's mid acoustic is a little bit more true sounding than kdx100-vsd3 imho but it is not the perfect earphone either. comes with 2khz frequency ampfilied which again is gonna need an equalizer to sound normal, but not as bad as them r1's bass is more deep oriented, not strong as the others thus we can count it is one of easy sounding models. frequency seperation is not strict as them either.
if you are not familiar with terms like "soundstage", "seperation" etc. i mean if you a newbie to this world. try reading reviews and advices carefully and buy a model, then try to understand above spoken terms with your own experience. only then you can start to analyse what you actually need and how to select the correct one. or you can try to buy & sell everything which is going to cost you a lot money as i experienced