Hello,
I actually developped a crypto to crypto exchange with my team, you can found out on fiverr/upwork but i wouldnt advise you to hire pajeets or nigerian.
The best would be to do it from scratch ( if you have the knowledge ), or some open source trade engine are available: viaBTC, Paetio exchange (on github) then you just need to implement the design u want and debug it.
If you want to hire a company, then take mostly european eastern solid team/american.