According to the specs, it should run fine. But I find it difficult to believe that Lightroom 3 is the only version available in your area. Adobe doesn't sell Lightroom 3 anymore. And it is three versions old. Where do you live that you can only get Lightroom 3?
Here is a link to the trial version of the last update Lightroom 3:
You can try it for 30 days to see how well it performs on your computer. But you won't be able to order it from Adobe because they don't sell it anymore.