"country of patenting" tells the whole story, and there is no real need to depart from the Russian.
In "country in which a given invention is sought to be patented", which is also idiomatic English, I had to insert "sought to be" because the description is of a process, in which there is no certainty that a patent will eventually issue. In contrast, "country in which a given invention is patented" or "country in which a given invention is to be patented" are both slightly presumptuous.

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Note added at 2 hrs (2014-10-08 10:18:01 GMT)
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"patenting country" is less desirable because it raises the incorrect notion of a country which is the active party in the process. As such, it is simply unidiomatic.