index.html and index.php in the same folder

Hello everyone,
I do have a very annoying problem.
In the root folder of my website i have a static html page.
Default document for this folder is index.html
I also installed wordpress in the same root folder (i just had to, don’t ask why 😉
So now i have two index files, one php and one html. Html is the default one.
Example here:
http://www.eksperciniveastyling.pl this page opens index.html
And if i want to view my wordpress i’m typing:
http://www.eksperciniveastyling.pl/index.php

The problem is, that most of the links in wordpress (link to comments, to archive, to user profile) doesn’t work 🙁

They’re redirecting me to the index.html page.

I noticed that they have form like this:
http://eksperciniveastyling.pl/?p=17#respond

It seems that index.php string is missing in this link, it should look like:
http://eksperciniveastyling.pl/index.php?p=17#respond

And if i type this url everything works fine.

So my question is how to fix it ? how can i have index.html and index.php working in the same folder?

Thanks in advance for your help,

Roch