Piotrus - $500 or 500 Euros is very low by American standards. Here, Iíd say that for a commercial foundry to make a mold from your clay, and then make one cast in bronze, fully finished, would cost about $700 for the mold and $1500 for the cast; for a total of $2200 for one cast, or $3700 for two. These estimates are probably low.
Most beginning sculptors here work with universities, such as in taking classes. That provides access to a foundry, and skilled help from other students in making the mold and the cast. Under those conditions, the mold cost would be mainly for materials, approximately $150, and the cost for a bronze cast would also be the cost of metal, perhaps as little as $150. Thatís closer to the cost you give, so you probably would be getting help from a student or art school.
The piece looks great, and I seriously hope you can find someone to help with a cast.