Bicycle rack for a rental car?

My friend and I will be cycling part of the Camino in July, 2012. We will be
bringing our own S&S coupled, short wheelbase, recumbent bikes. Our wives are
coming, and we will rent a car and do additional vacationing.

We would like to be able to transport our bikes on a bike rack on the back of
our rental car for times before and after we cycle the Camino. I have contacted
two rental car agencies so far (Sixt Rent a Car; Auto Europe), and neither provide bicycle racks for their rental cars. So, can someone respond to the following questions?

1) Is there a car rental agency in Barcelona that can supply a bike rack with
their car rental? If so, what company?

2) Is there a place (bike shop?) in Barcelona where I can borrow or rent a bike
rack to use? If so, can you provide a name (and even contact info)?

3) Is there a store (e.g., Wal-Mart or Academy Sports equivalent or bike shop)
where I can buy a bike rack when we arrive in Barcelona (Saturday, July 7,
2012). If so, can you a name (and even contact info?)

Any help would be GREATLY appreciated.

Buen Camino,
Wayne