Harrowed Spellstrike specifies that the range of the spell is changed to the range increment of the thrown weapon. Because 'Touch' is unfortunately a range increment, this means according to the book rules you need to make a ranged attack (not a ranged touch attack) with your cards for the spell to work. That sucks. This is also true of the regular Spellstrike ability, but that ability specifically replaces the touch attack granted by casting a touch range spell rather than the range of the spell itself. The base Spellstrike, then, allows its user to Hold the Charge (a property of the touch range), while the Harrowed Spellstrike does not and, in fact, loses all benefits of the Touch range.
However, you're in luck! The designers, addressing ill-founded concern over a magus's ability to use spellstrike at all (concern which clearly does not draw basis from the RAW) posted this:
Basically, the spellstrike gives the magus more options when it comes to delivering touch spells; it’s not supposed to make it more difficult for the magus to use touch spells.
Sean K Reynolds
This gives you some ground in trying to talk your GM into making Harrowed Spellstrike better in some way.