We were all newbies at some point.
Don't worry about the watt rating on speakers. It's more of a guideline than anything. It's not like that's the amount of power they put out. That is based on your receiver. In general, you can't really overpower a speaker, unless you leave it fully cranked all the time. Besides, the actual wattage output of most receivers doesn't reach the full rating given by manufacturers.
Any reason you want Sony speakers? I'm not saying they are bad, but I just want to make sure you don't feel that you need to get the same brand of speakers as your receiver. There are a lot of brands out there, and they'll all work fine with your receiver. Just pick what you think sounds best.
Good luck, and I hope this helps.