Peugeot 206 - Seeking advice - Najam

Hi Guys

Just found this forum and seeking some advice.

I got used 206 Peugoet last month milleage 52,000 with no service history.

After a month its gearbox slips and i can only see P, N and R on the display.

The gear lever moves to all positions and while phsically on drive position car can move but display is still showing R,

My local mechanic also identified that N/S driver shaft seal leaking and suggested to take the car to Peugeot garage for which i am planning to do for diagnostics,

Wondering if some one experienced the same issues and its gona a be an easy fix or an expansive fix with future risk with the gearbox?