The FAA will recognise your glider hours towards the PPL hours, and you could in theory get an FAA PPL in about 10 hours...
If I'm not mistaken, it is more like a minimum of 30 hours to add on the Airplane, Single Engine Land rating onto a glider rating. If you are already a power pilot, you can earn your glider rating with 10 additional hours. That was how I did it.
Search for e-cfr, pick title 14 from the drop down list, part 61, then the applicable rule is § 61.109 Aeronautical experience.
-- IFMU