Loss of power - turbo? EGR? sensor? please help

[Gibson2913]

Hi guys, recently bought an audi a4 on 110k miles. since buying the car for £2000, i have spent nearly the same in repairs and garage fees. it has not been kind to me.

Recently got the car back after having a new timing belt kit, water pump, 2 new camshafts, aux belt - the list goes on. within a week, my EML came on after dropping down a gear and i have loss of power after around 2600 revs, along with a flashing glowplug light. 

 

ive been told by a friends "mechanically minded" dad, that the turbo is goosed, but then i have also been told it probably will be the EGR Valve or even a boost pressure sensor! good to mention that there is no smoke on acceleration etc.

codes found when plugged in:

p0299

05171

 

confused is not the word.

Any help is greatly appreciated as i genuinely think im going to write the car off at this point.