Ozgur, it is possible that a powder has both T1 and T2.  Always remember that single crystals do not necessarily represent the bulk.  In your case, one tautomer may be less soluble or may just form the nicer crystal that was picked to do the single crystal x-ray experiment.  We often use powder diffraction to confirm if our single crystal is the same as the bulk sample.  

Powder XRD analysis will give you information that whether the bulk powder is pure T2 form or T1 form presents in the solid state too. For this, compare theoretical data [the pxrd pattern obtained from the single crystal data (we can generate it from Mercury)] and observed data [the bulk powder pxrd data. If it matches exactly, then in solid state only T2 form available, ; if some extra peaks observed in the pattern, then we can assume that T1 also presents along with T2.