Dariv,
Doug George did have Meg Gar mags for sale at a very reasonable price.
email: deg16@insightbb.com
They can also be found on the auction sites.
You might get a set of three mainsprings from Wolff.
website:
www.gunsprings.com
They have a set with one underpower, one regular power, and one extra power. Experiment with these to see which works best with your ammo. I have found that the cheapest Winchester brand that Wallmart carries works great in most of my Lugers. It comes in a white box and is the economy brand in either 115 or 147 gr.