hi peifang,
just a note, I stay near that park, currently having some major renovations, if you're considering a wedding this year at this park, you may want to re-consider.
Meet up with the exec in 2009 (dunno if still the same girl) but their service is not very good. Except for food, everything else (literally from wine, audio visual, decor and cakes) you will have to arrange on your own.
I had my wedding at One-Rochester Park. It's beautiful too.... without all the hassle.