"Saya mau dia di dekat saya."
Terjemahan:I want her near me.
Yes, "wanna" is colloquial and poor written English. It means "want + to". For example, "I wanna go home now." (I want to go home now.) It can also mean "want + a", but it is almost never written in this case. Say, but please don't write: "I wanna turkey sandwich." (I want a turkey sandwich.)
Kontruksi kalimatnya salah: 'wanna' adalah kontraksi (penyingkatan) dari kata 'want to' atau 'want a'. I want to eat = I wanna eat. I want a car = I wanna car. Jadi, 'I wanna him near me' = 'I want to him near me/I want a him near me' sudah salah. Jikapun 'wanna' dijadikan kata baku, tetap salah, karena susunan katanya sudah salah.