Burning Oil

[Hitchos]

Hi all,
now im no expert on engines so i need a little advice my car seems to be burninga lot of oil when i bought it (end of september 11) it was up to the max on the dipstick but i checked last week and was alarmed to see ot was below the minimum so i went to the local garage (whom im sure is only still in busy cause of me lol) and filled it up i did ask him if this was normal and he said for D-turbos of that age it was but now im not so sure :?

any ideas??