google & links to my page

Hi!

I've got a big polish site about chemistry (dedicated to students).
My page's URL is www.retorta.republika.pl, but I officially use & promote
this adress: www.retorta.prv.pl (because it's shorter). URL with prv.pl is
only an alias which is very popular in Poland (i'm not sore if an "alias" is
a good word here. I mean that the prv.pl is only a cover, page is in fact
under the first adress. The second, with prv, only connect user with
www.retorta.republika.pl and transfer him there). I'm sure that you know
what i mean because, as I suppose, some things like prv.pl are available in
other countries too.

And here's my problem. I know that the one of factors on which Google base
when it makes its page results is number of links to the site. Google
indexed URL with republika.pl on the end. In the Internet the prv.pl address
is propagated. So: is it a good thing to use two addresses? Can you tell me:
does Google treate addresses with prv.pl as republika.pl (or other "real"
URLs). Does it know that prv is only an alias? If not - i have no chances to
promote my site in Google - she know page as www.retorta.republika.pl but
never finds it because everywhere is www.retorta.prv.pl. Ughhh....

So can you help me in brightening my doubts? How does really Google works?

I will be thankful if you send answers for my questions also on my personal
e-mail. Thanks.

Mat