Lets be honest your playing thru a Computer speaker system....

secondly if you take your music seriously you can't skimp on sound reinforcement its the most important thing in your rig......get yourself a nice set of powered speakers.....& for multiple players in a small gig scenario which requires a mixer maybe something like the Yamaha Stagepas Series would work nicely for you...for an all in one.
http://www.yamaha.com/yamahavgn/CDA/List/ModelSeriesList/0,,CTID%25253D560071%252526CNTYP%25253DPRODUCT,00.html