How to create attachments page template switch?

How to create attachments page template switch?

I've read several post over this topic, however, none have provided me
with an answer. Firsly, let me say that I'm a noob in php programming, but
I managed somehow to rewrite my html site to wp theme. Anyways, I'm facing
some problems now and forgive me for my step-by-step writing, but I want
you to understand me, totally.
I have a spalsh page and my website is divided into two parts, one in
english, another in polish. For that reason I've three templates: first
for splash, second for eng version and the last for polish. The eng.
version template is a default.
The gallery I've created on one of the pages in polish opens each snap in
default template, whereas I need it in polish. On the other hand, I'll
later prepare the translated version, where I'd need it in english. I know
that the page where the snap is being opened somehow refers to
attachment's template, but this cannot be set simply using wordpress
managing panel. And here my questions are:
1. Are there any plugins for that problem? or
2. Do I have to build my own attachment.php?
3. How to let the wp know that I need a particuliar template for
particuliar gallery?
4. Could someone help me writing some code?
The page with gallery could be seen here:
http://rrozzy.0fees.net/?page_id=104
Thanks in advance,
rrozz