I returned from the US with about 800 hours and I'm doing the "conversion" course now.
Basically 14 monster books (one exam per subject), I think you have to go through 650 hours of theory for the JAR-FCL atpl course, where about 500 of them can be distance learning, and the rest I'm doing in 3 weeks of groundschool lessons.
After that comes the checkride to convert to cpl/me/ir, which is (in my country at least) 10-30 hours before checkride.
Everything included, cost me about $20 000