I need a very poor photo improved

i have a very old and poor quality photograph that i'd like improved. i have had several done before.
i am quite good with photoshop myself but feel this is beyond me.
i'm aware that i cant expect too much due to the quality of the original but i know there are some talented people on here.
i'm not in any hurry as i will have limited access to my laptop for the next couple of weeks.
many thanks