Speaker system for netbook

Please excuse if this is not the correct forum for this "non-Apple" question. I have an Acer Netbook which I use for multi-media presentations to a group I belong to. This group is about 120 strong and meets in a hall about 35' X 70'. I need to get a pair of speakers which I can plug into the netbook and which will have enough power and amplification so that what is spoken into the microphone can be clearly heard 25 rows back. The local Best Buy suggests the Bose Companion 20 or the Creative T40, but I am sure there are others. Audiophile sound quality is of secondaty concern; primary requirement is ability to be heard clearly 25 rows back!
Any and all help will be appreciated.
Kevin

It may end up being easier to find a venue where there is a built-in system. By the time you get an amp, at least 4 speakers (2 for the front, two for the back) you could end up having a logistics nightmare.

IF I was doing this, I would invest in an inexpensive tuner, 4 speakers and the cable to run the speakers. All this is equipment for home entertainment centers. All of which you can get open-box and demo items at places like Best Buy or HH Gregg. Run the back speakers and front speakers off the same channels so they receive the same audio. Just hook the PC into one of the line in and go. You should then have all the volume and clarity you need for presentations.