iPod Airtunes fully wireless/outdoors?

[adesinacat]

I would like to be able to use AirTunes, but right now I only have one Express that can't go any farther then the hall to still be in range. Where I would like to use them is outside when I am working on the garden and in the garage when we are cleaning/packing for a trip. I really can't afford to spend a lot (over $100) right now. I would like something that could be mobile so that I don't have to keep the speakers and such outside all the time. I live in the Pacific NW, so it rains to much for that to be a good idea. Is my best bet to just get some low quality speakers and an extra Express? Are there wireless speakers that are less then $300? Sorry to all the music purest. I just want to be able to hear the music, not have it be the best sound you can get without being in the studio.