Hi, I have already integrated Payumoney payment gateway to one of my client. You can check their website www.himtcollege.co.in. That design is done by their in-house team. We have done payment integration. They bought the gateway from Indusind Bank. Also I have integrated other payment gateways like FSS (Hdfc bank supported), EBS and ATOM.
Also I will help you on document process to get the new payment gateway account.
Please do chat me for more details.