Unfortunately calibre is doing stuff on my computer so I cannot test this , but it's possible that one of them will work for both titles as is. I assumes that in 1 the title is Gunslinger and series# 01 and series The Dark Tower, while in 2 the title is Harry Potter and the Goblet of Fire.
01 is proceeded by " " and followed by " - ". Let me know if it worked, if not I can try playing with it after calibre stops working.
(?P<author>[.]+) - ((?P<series>[^0-9]+) (?P<series_index>\d+)? - )?(?P<title>[.]+)
or
(?P<author>[.]+?) - ((?P<series>[^0-9]+) (?P<series_index>\d+)? - )?(?P<title>[.]+)
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