US Airways definitely DOES NOT have any access to Varig's seat maps. For starters, Varig has many versions of their aircraft, so make sure you call Varig again. There are some of Varig's MD-11 aircraft that are actually former Swissair aircraft. Again, call Varig and find out. If you are on a MD-11, ask how many first class seats there are. If the MD-11 has 12 seats in First, then it's the Swissair version which has nicer seats. If on the other hand, the MD-11 only has 6 seats in F, then you are on Varig's version which is not so nice.

I have flown Varig before using my dividend miles and Varig reservations office was able to assign me seats in advance for all legs of my trip. Try calling them again.