Asking for more money

So I just started a travel assignment at a prison not too long ago. I like the job but for a traveler the pay is low compared to other places. I know the rates everywhere are going down but an RN was making over 4K weekly for months while he was there when COVID first hit. I am getting no where near that. I feel for a traveler anything less than 2k isn’t worth it, especially as an RN. I know when it’s time to extend the contract I can ask for more but how do I go about it? Do I tell the recruiter and she will try and negotiate on my behalf? Does the HSA have the power to increase the wage? Obviously if I can’t get them to raise it I’ll go somewhere else but this job is nice and I would like to extend it if possible. This place is desperate for nurses and almost everyone is a traveler so I know I have the upper hand in negotiating.