"Do you get more installs if you publish the app to the stores for different countries?"
Yes, naturally. But as Frosty says, choice matters and it's not always worth it. You have to consider the number of people worldwide that speak the language you're considering, and unfortunately how rich the target countries are. You might publish your game in Russian, which is spoken relatively widely, but they're generally not wealthy and aren't interested in IAP's or clicking through ads to products they can't afford.
I have a game on the App and Play stores that's available for free in 11 languages. That gives it a large potential audience. However 75% of its players over the game's lifetime are in English-speaking countries. Additionally 80% of the game's advertising revenue has come from English-speaking countries. So while I think it's cool that the game has been around the world in all sorts of languages I can't understand, financially speaking it wasn't a wise move (the money that's come back from non English speakers has not covered the cost of the translations).
"If yes can you just use Google translate to translate the english description and paste it into the description for different countries?"
A big resounding "no" here. Google translate is still very nascent, and it screws up a ton of stuff. It does a passable job (not "good") for languages that are somewhat related and have similar grammar (English to Spanish, for example). Forget anything like English to German and certainly anything like English to Japanese (even people that speak both of these languages natively sometimes have trouble relating concepts from one to the other). If you're serious about doing it though I'd recommend finding a paid service of some kind that has actual humans involved in the work.
"What I need to nknw is will Googl penalise for a bad translated text?"
I have no idea. I work in SEO and I can tell you that Google is not in the habit of sharing it's decision making processes for rankings.
"Also if you make the game available in those ohter stores do you then have to provide the in app text to match that lanaguage?"
I don't think so, but it'll certainly help appeal to Korean speakers if they can actually read the app description.