Hi colormeprettyy, my sister goin to have her wedding in JB. From what i gathered, there's lotsa places that could easily cater your number of pax.
If you're looking at hotels.. there's puteri pan pac, grand paragon n thistle..to name a few. There are also halls like the dewan jubli intan (most famous for weddings), while the newest is the hall inside the English College School.
A wedding planner would set you back at around rm24k (was quoted for my sister) for the whole she-bang...(u just need to provide the door gift).
Hope this helps.