Revamp C# POS Interface

I have an existing point-of-sale application written in C#. The current screens work, but the layout feels dated and slows my staff down. I need the entire interface rearranged so it is modern and intuitive... (Budget: $250 - $750 USD, Jobs: .NET, C# Programming, C++ Programming, Software Architecture, Software Development, UI / User Interface, Visual Studio, WPF)