Elaine, if you aren't really attached to your furniture, there are things that you can do to help make them match.
1. Stain. Sand it all down and restain it so it all matches. This can be time consuming, but if you like the look of wood, it's the best way to go. And it will look like new when you are done. If you do this, it won't really matter if the wood is different styles. None of my tables match, but they are the same cherry wood color so they still look ok together. (I would say they look great except they are over 40 years old and very scratched up.)
2. Paint. Painting you furniture and then sealing it can also make it match. It's also a great way to bring some color into a room. An inexpensive way to do this is to check at your local home store for "odds and ends" paint. This is paint that people had mixed and then didn't like. The home store will sell it really cheap to get rid of it since they can't do anything else with it.
3. Slipcovers. While they can be expensive, they are infinitely cheaper than buying new furniture. And they will give your couch and other pieces a whole new look. And if you can sew, you can buy patterns and make them yourself.
4. Throws. This is what I use since I can't afford slipcovers just yet. Get some larger throws in a color you like. Drape them over the back of the furniture to trail down the front and over the seating cushions. While it won't hide everything, it will help to tie pieces together. You can get them in just about any color these days, too. And when you finally can get rid of your old stuff, you will have some great throws to use!
Just a few ideas. Hope this helps!