Sounds like your compression is set too high on your jpegs. That generally causes the halo effect and blurry edges. Also, if you have large areas of a solid color, you may get lots of speckling and splotches around edges with .jpegs. For example - a jpeg with a white background is NOT going to look the same as your web page's white background 90% of the time. It'll always be just a little off. Get into large areas of reds and blues - and you'll see it turn ugly real fast.
The very nature of jpegs is not of crystal clarity when used for web work - rather it is to handle a multitude of colors with reduced file size. Oftentimes, you'll get better results with a .gif - just depends on the image you are working with. Jpegs are best used on mutli-colored images, whereas .gifs can handle the large solid area colors better, though the number of colors is limited. That's where working with color palettes comes in.
Setting a palette, if you can, may help resolve some problems you may be having with areas of solid color, even in jpegs. You can tweak and poke and probably get better results than you are getting now.
There's gotta be a way to sneak a copy of Photoshop or Paint Shop Pro to where you live, isn't there? Paint Shop Pro has trial downloads from many locations across the net and is a very nice program with a small price tag. I've even done magazine ads with it. If you become familiar with it- you'll be surprised what magic you can do.