Which .DLL out there would allow me to spice up the whole interface of mIRC in other words I want to make a custom interface with GFX as well as custom DIALOG's ?

Generally a good idea to search for stuff before asking.

http://www.mircscripts.org/ -> Search (BUTTON) -> "Dialog"

The very first .dll that comes up is "DCX," many people use this to modify their dialogs. (Though, I personally don't use it.)

There's not a ton of DLL's on the site, but you can browse through just the .dlls and see which do what by reading their descriptions.

Actually, i've been on that site and downloaded various dll's as per description and its not what im looking for example, there is a MTS dll which is not what I need however I did not see the DCX at the time I will search for it and see what I can do.

Thanks