Well, the second article I linked mentioned:
Within 40 miles of the damaged wellhead, the oil deposits appear extensive but patchy.
So it's likely they took at least one sample forty miles out (for the record a forty mile radius would be about 5000 square miles so obviously they didn't do uniform sampling over all that area). Hopefully the report itself will have more details, unfortunately I haven't been able to find a copy online anywhere.
As far as I can tell Dr Joye though seems to me fairly level headed and the media has been a little overzealous in reporting on her work. Even she admits there won't be any lasting damage saying “The Gulf is resilient" and “I do believe that it will recover from this insult, but I don’t think it’s going to recover fully by 2012." I believe she just wants people to realize that the damage was more extensive than reported and we may not see the full effect for a couple of years yet.
Another thing she pointed out in an interview she did was her sampling technique appears to be more precise than those typically used by BP and others. Apparently the "pools" of oil are fairly delicate and can be blown away if you don't take your core very carefully (i.e. slowly). BP re-measured several of her sites using her technique and came away with the same results she got. If anything, this should help improve the process used to monitor the area.