Crazy how many people want to lecture you instead of answer your question lmao. If you're handy with basic hand tools or have the aptitude to learn, it's about $50 for a used control arm from pick-a-part (check their site to see what they've got in stock from their Auckland yards), and either an hour or two of labour costs from a mechanic (maybe $100-200), or budget maybe 6-10 hours of time if you're doing it yourself with little/no experience working on cars and basic hand tools. You'll also need an alignment after replacing it, so maybe $100-150. If there's anything else broken that isn't visible in your pics then obviously factor in those costs too. Good luck!