Don't go by wattage, cheap speakers will sound bad no matter what the vendor states for the power. Usually the power is way overstated from what they actually put out in the usable range.
Even if you want to listen across the room from the computer, the altec lansinsgs I linked will be fine.
These may be louder http://www.flipkart.com/creative-sbs-a335-2-1-multimedia-speakers/p/itmczzcahzh9zekg?pid=ACCCZZC9BDUM4EXE&ref=ba17a007-103b-4b04-b262-df68f0c34fc5
I would stick with Altec Lansing, Creative or Logitech speakers for the lower end.