Stick the key in the door lock and turn it to unlock the car. Get into the car, put the key in the ign and turn it within ~20 seconds or the alarm will go off. Start the car and use the release lever/switch depending on year.
Your car may have "gone to sleep" after the week. If everything works after the above that is probably what happened.
If not your remote may need a new battery or it could be broken.
If you put new battery(s)in it and it still does not work you will need to buy a new key head and have it programmed at the dealer. Total ~$300.
Sunset Porsche sells the head for ~$130.
Portland Oregon Porsche Dealership - New & Used | SUNSET Porsche
You will still need to get it programmed to the car. If you buy one on EBay or... make sure it comes with the 18 digit barcode label or it is useless.
Some dealers will include the programming with the purchase, most will charge $125+ for programming.