The cost of the conversion will most likely exceed the value of the vehicle, even if you already have a transmission.
Seeing that you had to ask this question in the first place it is unlikely that you have the mechanical skills to do this yourself. The rate for a professional mechanic is about $100 per hour. I would expect a professional to be able to make this conversion in about 8 to 10 hours if everything went smoothly. So figure on about $800 to $1000 for labor alone.
In addition to the transmission you will also need a new flywheel, clutch, pressure plate, throwout bearing, shifter, clutch / brake pedal assembly, clutch linkage, transmission mounts, and drive shaft. Figure on the additional parts costing another $2500 to $3500.
Figure on another $300 to $500 for unexpected items.
So you could figure on the entire job costing between $4000 to $5000.
In the end you truck will be worth no more money than it is now, maybe less as you usually deduct for a manual transmission.
You would be better off selling this truck. Add another $3000 to $4000 to the money you get from the sale. And buy a newer truck with a stick if your heart is that set on shifting gears.
