How do you get these achievements?

Spreading it around Spread your disease to 5 other user! 0/5

Shop Benefactor Help a shop stay open during the Zombie Plague, by donating 5 Lamouracillin!

^ does it matter what shop I donate to?

Heart Collector Collect 1 Candy Heart from a users profile!

^ I don't know how to do it xD

As far as I know the 'Spreading It Around' and 'Shop Benefactor' achievements are retired (they were available in 2009 but not in 2010). The 'Heart Collector' achievement may be available later in the event although I just looked at a few profiles and it does not look like candy hearts are up currently (when they do appear they are in the contact section where the mail and add buddy buttons are and you can click on and receive a candy heart food item).

The first wave of Zombies (in 2009) bit others to pass on the virus instead of it being just a random event. They don't use that method anymore so you can't get that achievement.

Alright :3 Thank you both!

No problem :)