H1 heading converts automatically into h2 ?

I am having this title on my homepage: "<h1>Garažna Vrata - Kupovina, ugradnja i stručni savjeti</h1>" : http://www.ka-mont.hr/, but when I check i the source code with firebug its states: <header>
<h2></h2>
</header>
<h2>Garažna Vrata - Kupovina, ugradnja i stručni savjeti</h2>

how can I adjust this as I really want my first Heading to be H1 with my main keyword included?
Thanks

Hi.
Block with "Garažna Vrata - Kupovina" is a module or article?

p.s.
For Google it doesn't matter if he find H1 or H2. H1 - must be only one on page.

Some facts:
1) For article view we used H1 for article titles
2) Modules uses H3 for its titles