this is the code:

void Import_files()
{
OPENFILENAME ofd;
char buf[256];
FillMemory(&ofd,sizeof(ofd),0);
FillMemory(buf,256,0);
ofd.Flags=OFN_PATHMUSTEXIST|OFN_FILEMUSTEXIST;
ofd.lStructSize=sizeof(ofd);
ofd.hwndOwner=hWnd;
ofd.lpstrFilter = "Models *.x *.obj *.tga *.bmp *.pcx *.dds\0*.x;*.tga;*.bmp;*.pcx;*.mdl;*.obj;*.dds\0\0";
ofd.lpstrInitialDir = "Import";
ofd.lpstrFile=buf;
ofd.nMaxFile=255;
ofd.lpstrTitle="Import Models";
if (GetOpenFileName(&ofd)){
ent_create(ofd.lpstrFile,vector(camera1.x,camera1.y,NULL),bu_pan);
}
}

but i want to add New Formats like .fbx and .3ds plz give me the way