The closest parking is at the Pangea parking structure (street-level and roof level) at the corner of Pangea Drive and Scholars Drive. It is located about 2 minutes walking from Institute of the Americas.
Pangea has parking permit pay stations located in the structure. The cost is $1/45 minutes, so you would pay $4 for 3 hours of parking, $5 for 3 hours 45 minutes of parking, $6 for 5 hours of parking. After 11pm, no parking permits are required.
The cheaper option is to buy a One-Night Pass for $3. These passes are valid beginning at 4:30pm. They are only available at the North Point Drive visitor kiosk. To get there, head north on North Torrey Pines Road. Turn right on North Point Drive and go about 2 blocks. The kiosk will be on your right, in a roundabout.