3D structures for heterodimerized proteins

I would like to make 3D analysis for my polypeptide chain, with its heterodimerized another polypeptide chain together with DNA segment containing recognition motif.
That means I want to input "fasta format of protein 1 + fasta format of protein 2 + DNA;
this is something lile "Hoxb1 + Pbx1 + DNA".
Could you pleased advice me how I can do this.
Oya