TDP - fitz roy

hi

i'd like to spend time at fitz roy after doing TDP, would just like to know how easy it is to get across the border into argentina and back again into chile. Are there bus companies that would do the trip from TDP to fitz roy and how long do they take? Is there any way i can fly from somewhere near fitz roy to santiago?? Also, as a british citizen, do i need visas for either country??

cheers,
adrian