Yeah you're going to need to learn CSS/XHTML to work with WordPress. I'm sure you can use Tables with WordPress, but let's not even talk about tables.
Um...everything you need to learn about CSS/XHTML is going to be online. Though, if you do like to read off the computer, grab a book.
You start off by heading over to the links below and that'll give you a good start.
http://www.html.net/tutorials/css/introduction.asp
http://www.w3schools.com/css/css_intro.asp
http://www.html.net/tutorials/html/introduction.asp
http://www.w3schools.com/xhtml/xhtml_intro.asp
I hope those help. Take it one step at a time and just try and absorb as much as possible. And remember to take breaks.
If you have any questions, feel free to message me on MSN or AIM.