Hell, this isn't a question, it's just info for the next person who is in Hong Kong and wondering where they can buy a parasol for a wedding.
There's a couple of shops on Peel street in Central that sell Chinese lanterns, fans, knick knacks and parasols. I like the guy on the g/f of 21 Peel st (25423109), and he had pretty paper parasols for HK$38. There were also some slightly more garish, bright coloured nylon ones as well, for about the same price. He speaks English and says if you buy 20 or more he can do a 20% discount.
There's also a store at 94 Bonham Strand East which sells household stuff, and they have a bale of lacquered paper parasols out the front for HK$10 a piece.