which one should i buy the first one or the second one?
is the second one better then the first?
i played the first one like 4-5 years back in russian but seems like i cant find the disk

The two are quite similar but most players feel the second is better. If you're only going to buy one of them, that's probably the one to get.

I've only played the first though so I don't know firsthand.

I have both games, and find I much prefer the second game to the first. Most of what was good in the first game have been implemented into the second, along with the music and gameplay. The main difference I found was that there are fewer FMV sequences (The taking off from the hanger, etc) and a complete removal of the Hyperspatial anomalies. Instead you have the Black hole, which is the same thing except you appear in another location once it is done and only need to enter it once. Makes traveling to other sectors a lot easier.

Hope this helps

And for some people, GOGs SR2 simply does not work (though Reboot cured that problem for me).

The games are very similar, with the second one being a light upgrade. By this I mean that its graphics are a little more polished (in my opinion) and has some extra depth.

I recommend buying both as they are EXCELLENT games. I have Skyrim and a few other 2011 releases sitting around unfinished and I have over 50 GoG games bought and these two are by far my #1 games. I also suggest playing them in order (the 2nd will spoil the story of the first), but if you absolutely cannot, then get SR2.