There are so many different products you could go with for this. Only problem is the products are usually really hit-or-miss. When I finally found one that worked well I ordered as much of it as possible.
Leather Magic, the name describes it perfectly. I used the delux kit a few times before ordering the pro kit. The delux kit sells for about $59.00 and it's ordered in the exact color that you need. They have a color chart that lists vehicle make and model so you can make sure to get the exact color of your vehicles interior.
Don't forget...
Before begining the repair make sure to read and follow any and all saftey precautions neccessary for whichever product that you decide to go with.
Keep in mind that it is required that you let the repair cure for 48 hours before sitting on the seat.
Repair Process
- Clean the seat thoroughly using a nylon brush and cleaning detergent
- Use the same soap you use to wash your car
- Sand the areas being repaired using the supplied 220-grit sand paper
- Apply the paste and fill the damaged areas
- Sanding may be required between applications in order to ensure that it's a smooth finish
- NOTE: This process is critical when determining how the finished product will look. Make sure to take your time and get the surface as smooth as possible before coloring
- Color
- Use as many coats as needed and again, take your time
Before

After

The before and after photos above do not show the rips that your leather seat has, but this product should work just fine.
Remember...
If you go this route then make sure to get enough of the Linen Subpatch Material. You can get sheets of 12"x12" for around $2.00. This material is used for patching thears and even holes in the leather. And if there is material missing and you need leather they have that as well in their individual items section.
Linen Subpatch Material

Use this material to stuffing material in the seat. Think of it as
foundation a house, it will be exposed but if it's uneven the house
will be crooked. I cannot stress it enough to make sure to take your
time and make sure that when the Leather Filler is applied it does
not look like a swell or cave in.
Leather Insert Filler

Use this material to fill bring the hole / tear back together. Try to use as few > peices as possible. Don't cut 10 peices to fill a 1" hole. When you first cut > the filler cut it too big and trim it back with a razor blade. until it just > drops in, then proceed with applying the puddy material and finish up with a few > layers of paint.