Would recommend you concidering 2 things that can be done about it without increasing production costs:
- Ask people on zog (zone of games), they made a lot of nearly perfect fan-made translations for telltale games, life is strange, and other titles that did not had official translation - for example, tanslation of Nier - Automata (with lots of text) took only big more than month for them.
- When you establish steam page and forums, you may just ask for community help. Developers of Warhammer Regicide did that, and i was a part of that translation team, and i can say from my own expirience - community-gathered team, that correcting each other's mistakes and discussing unclear moments with developers doing job pretty well and fast, all you need is stringhub, + make them sign nda. Regicide didn't sell very well for various reasons, but translation wasn't one of them - people never complained about it, and dev's rewarded all translation team with several keys as a reward for the help. So just asking people on steam forums could work out well too, especially concidering that your translation is already done, and all what is needed - a little correction here and there to not lose atmosphere of the game.