Can you use this:
line = "\"NAME\",\"610 \"A\" STREET\",\"STATE\",\"POSTAL_CODE\""
regexp=/(?=[^,])"|"(?=[^,])/ # (?= is for maintaining the character that is
not a comma)
a=line.gsub(regexp,'\1'+"'"+'\2') # \1, \2 are the first and second matches
in brackets
regexp=/'([A-Z])'/ # if the address is "610 A street"
b=a.gsub(regexp,'"'+'\1'+'"')
p line
p a
p b
Best regards,
Axel