You have to either:
1. Find a Renamon mercenary egg and the right amount of data and try to hatch one on your own.
2. Purchase a Renamon reinforced egg from either the main site using silk, or from other people(which usually costs around 2t for 3/5, 10t for 4/5, and 22t for a 5/5).
I actually recommend saving all that money for a reinforced egg. It's a sure way to hatch an egg. Especially with Renamon, who takes more data for each injection.