Please help me, would like to shorten the strap on my Miu Miu

Please could anyone help, I have a front pocket tote please see picture and would like to wear it across my shoulder but the strap is too long and I am short (5ft3) so it comes to my knees when I wear it. Is it possible to have the strap shortened and where do I go. I bought the bag from e bay so not able to go back to the shop where it was bought, help!:sad:

 
My Harlequin bag has an adaptable strap and I had two extra holes punched in to make it shorter (I'm 5'6 and it came to mý knees).
If you can't just have extra holes punched then you can ask any good cobbler to shorten it for you, the ones worth their salt can do a lovely job on that. Otheriwise mabe find a shorter strap and have the colour matched to your bag?
 
thanks MiuMio the strap cannot be adusted, i thought about taking it the cobblers to have a hole punched but even if i did that the strap is sewn in place so i could not bring it up to meet the new hole. I know a good cobbler that might be able to shortern the strap, will have have to take it there.