Help in User Interactive Topic Forms

Hi,

I’m developing a website and i’m searching for plugins and themes for wordpress but i need help in this particular case.

My website will have Interactive Topic Forms but i don’t find any theme with this, can anyone help me?

I sketched a simple Page Layout for you to understand what i need.
Basically we want a page with categories, and in the body we want to show topics with some info and a thumbnail, but if is a Registered user we want to show the buttons, and the main button is the New Topic, to create a new topic with the info.

You can check on the below links the Page Layout.

[url=http://postimg.org/image/tli5fkt5t/][img]http://s32.postimg.org/tli5fkt5t/Ecra_Add_New_Topic.png[/img][/url]

[url=http://postimg.org/image/cjpbdheap/][img]http://s32.postimg.org/cjpbdheap/Ecra_Home_Page.png[/img][/url]

[url=http://postimg.org/image/bwqenyhep/][img]http://s32.postimg.org/bwqenyhep/Ecra_Sub_Cat_Selected.png[/img][/url]

Thanks & Best Regards,
Andre Carvalho