For my first project I plan to redesign my father's business site
Eeeeek! I think that is a colossal mistake. That's almost like saying "I'm real good at making lamp shades. For my 1st project, I think I'll re-do the electrical wiring in my house." If this business is important to your father, I think he would be much better off hiring a professional web developer.
1) At a minimum, you need to learn all you can about X/HTML and CSS.
HTML & CSS Tutorials - http://w3schools.com/
CSS Positioning in 10 Steps
CSS Box Model
2) Don't let Photoshop or any other graphics app build your HTML code for you. It doesn't work in the wild. Use graphics apps for comps, slices and optimizing images only.
3) Spend a couple of months learning how to use DW to build web sites. The more coding skills you bring to the table, the more you'll appreciate what DW can do for you.
Adobe TV - Learn DW CS5 (video tutorials)
Creating your first web site in DW CS4 -
Taking a Fireworks (or Photoshop) comp to a CSS based layout in DW
Adobe Developer's Center - Getting Started tutorials
4) After you've built 3 or 4 test sites that perform well in all devices, you'll need to get up to speed on Search Engine Optimization (SEO). This is crucial to the success of a web site. If done incorrectly, you could do irreparable harm to the business. I know this for a fact because I've had to go back later and FIX damage done by well-meaning offspring who didn't know what they were doing.
Thanks for your response.
I was looking for a quick band-aid and found it, but thank you anyway for your thorough suggestion.