The first place I would check would be eBay or Craigslist to get discounted used speakers. If you'd rather go new, Amazon has good prices, but BestBuy has good customer service in case things go wrong.
Not all speakers have the same decibal range. According to speakers that I was able to locate online (BRG wireless) the decibel range is 99dB. However, other brands of speakers may be different.
Wireless speakers can be purchased online through auction sites, craigs list, or on the manufacturers page. Electronic stores also carry many products, and may even offer coupons and discounts.
Wireless speakers and other wireless electronics can be found at www.amazon.com for very good prices and a lot of times even free shipping. You could also check www.ebay.com.
There are several high quality wireless outdoor speakers you can choose from they include Rocketfish, Schooner II, Yamaha and Mutant to name a few.
Korus wireless speakers are one of the great standalone speakers.
Good quality wireless speakers can be purchased from www.amazon.com. There are a number of good brands to choose from. Check out models by Sony, Logitech, Audio Unlimited and Yamaha.
You can go wireless, but you will have to buy wireless speakers. There is no current way of upgrading from wired to wireless and keeping the same speakers. The only way I can imagine is to buy some wireless speakers and then dismantle those and add the pieces to the old wired speakers, the ideal outcome, making them wireless and using the same good quality speakers that came with the stereo.
Wireless speakers tend to cost more than traditional speakers because wireless speakers use more advanced technology. Wireless speakers are less restrictive as in they can be placed anywhere in your home and can even be transported more easily when you travel with the laptop.
Yes, Bose does make wireless headphones. You can find them at major department stores, best buy, or sharper image, I do know that they are expensive.
A lot of sites online give good deals on electronics. http://www.zdnet.com is a good site to get items which are in good condition and are at a reasonable price. This would include Bose wireless speakers.
You can get a couple of different versions of wireless speakers the WL6000 - Dell 5.1 Surround Sound system and the SoundOn Media 210 wireless USB speakers.
One could purchase wireless computer speakers in many stores - such as Target, Walmart, BestBuy, Sears, Apple stores, Microsoft stores, or online, at stores such as Amazon or eBay.