Does anybody know where i could get a mono amp an 4ch amp and subs or sub and some 6x9 and 6 1/2 splits. im updating my car stereo and i wanna add a few extra things. or if any one mants to sell let me know cheers.

I would start by visiting a shop that sells car audio...

First, think of a budget.
Then depending on your budget and location, visit a few stores.
Want some entry level stuff that'll do the job? Go to your JB's, Strathfield, Supercheap, etc.
Want some speciality advice, then check out your local specialty stores, I'm not aware of any in TAS.

with the amp I am selling you, be sure to make sure to find an ideal subwoofer to match it. You will want a Dual 4ohm, or single 2ohm woofer, which are quite common among different brands. Also something that operates well at around 400W RMS will be ideal.

As a basic cheap sub that would be well suited, I would suggest the likes of an Alpine Type-S or Type-R. Second hand they can be had quite cheaply, and if your used to listening to a fairly standard stereo, you will find it very satisfying.

you still selling that X damo?

really havent decided yet tbh, its sitting around and if i can be assed ill fiberglass a box for it, but if i happen to get an offer i like in the mean time then i may be inclined to selling it.