Easy way to attach address and data bus to the outside world ?

Given that you're living in the dark-ages of using block diagrams, then you only have yourself to blame :)

If you also code the top-level in Verilog, you're done, you just need a Tcl script with the pin constraints.

Take a look at this tutorial, it has an SOPC/Qsys system integrated with a top-level design, along with simulation and synthesis scripts:

http://www.alterawiki.com/wiki/using_the_usb-blaster_as_an_sopc/qsys_avalon-mm_master_tutorial

Cheers,

Dave