Many Thanks RexHavoc!
looking on the web, I've find this (the first):
http://www.modestmagic.com/tags/alienI think, that removing the stairs and adding some access platforms for infantry and tanks will be a good start.
I don't know where I'll find $319.00, hehehheeh.... but I can search the first bank for a robbery.
Jokes aside, the price is acceptable for this kind of scenery.
Starting from this point, I imagine at the center of each structures an High elven spires tower, to expand in height the design of the citadel... Elven tower, but not properly fantasy, they could be without more details, neutral, they can came after in the last step.
For the details I'm thinking at beads and similar to stick on when all is painted.