How to simply integrate a customized jQuery Theme made with ThemeRoller in Drupal 7

How to simply integrate a customized jQuery Theme made with ThemeRoller in Drupal 7

I'm a pretty noob in Drupal as well as in jquery. My knowledge in html is average and in css rather little. In php I can copy / paste a code snippet but not much more until now. 

So I've been trying everything out for a couple of days to simply get some jquery script working as desired in Drupal 7. I started with a simple accordion snippet and I finally managed to have it work. (Maybe it's something to obvious for having some guys writing a understandable 'how to' about it for dummy newbies...)

Now my problem is that the original style is absolutely horrible and it does not fit at all in my website theme so I wanted to tweak it somehow. With Drupal this is something apparently very komplex to do. With Firebug I could localise the css files and I could modify parts of it to change the accordion style but I think it would be much more comfortable to use the ThemeRoller and it's personalized css file(s).

I have been trying to paste the code of the jquery example page (within the personalized custom zip made with ThemeRoller) in my drupal node (using the php module and text format since this was my first big mistake) as well as to put the needed files (jquery-ui-1.8.11.custom.css, jquery-ui-1.8.11.custom.min.js and jquery-1.5.1.min.js)  in the proper directories on the webserver. I think the files are loaded correctly but the css modifies all the style of the node (not only the accordion) and the accordion is only partially styled as it should. It seems like a nice mix with the drupal (Bartik) css and maybe the cascade does not go in the needed direction.

I searched quite a lot about it but could only find posts from other people like me trying to have it work as desired and not answers. I cannot imagine that I am the only one having this problem?!

Could someone please help me out to find the needed solution.

Thanks a lot!!