Bielsa is in a very expensive part of Spain. The valley hosts the preferred ski-resort for the Spanish royal family and the Madrid upper class. Even the campgrounds in Bielsa are rather expensive.
The best lodging I've found is the auberge in the absurdly beautiful village Sin, about 10 km east of the main valley. Look for Albergue de Sin on google/booking.com.
The (only?) guidebook for the area is
Grimpe en vallées d'Aure et du Cinca. Otherwise you can look for the hand-drawn topos in the bar in Salinas, near Devotas/Superdevotas, which is nice if you want to have grades that are less french...
After this winter I think there will be a lot of seepage well into late May, but I'll try to ask around.