used car warranty issue

[lenard]

i bought a car a month ago from a local trader and he sold it with a 6 month aa warranty, it now needs a new dpf and some other parts, aa warranty will only cover 367.90 of the claim which comes to around 950pounds. do i need to pay the difference or can i ask the garage i bought the car from to pay the shortfall?

thanks

[lenard]

bought 1 month 2 days ago. eml came on last week and car went into limp. called dealer they said contact aa warranty they said book into local garage and let them send costs to them.
garage have looked and dpf has broken down inside and needs replacing.