Continue from http://worldbuilding.stackexchange.com/questions/59315/how-to-defend-a-phone-booth-against-horde-of-zombified-carnivorous-dinosaurs. (This question concludes the time traveling phone booth storyline.)

After some times I made a shocking discovery that an **Albertosaurus's sperm** can prolong the phone booth invincibility even after the trial has ended, every hundred millilitres of the sperm used to coat the exterior finishes grant the booth up to 30 days worth of invulnerability. I know you are afraid of what's coming... how can I retrieve at least 1 year worth of the undiluted Albertosaurus's sperm solo?

Assuming I can only managed to raise USD$2000 from crowd funding to be spent at any legit hypermarket in the USA, killing is strictly prohibited. Albertosaurus belongs to the genus tyrannosaurid family which happens to be closely related to Rex. Handwavium shall be applicable exclusively to the time traveling, invulnerability abilities and my own collection of the exotic sperm sample.

Difficulty: ⭐⭐⭐⭐⭐⭐⭐⭐⭐⭐