Nav 510 newbie question

I'm about to buy the 510 but have a few questions you might be able to help me with -:
1. I believe the kit comes with a 128mb SD card with Uk map, is there enough room on this card for POI's (petrol, cameras, hospitals,etc), about 6 in all?
2. If not, what size card should I get?
3. Is it advisable to buy a card reader?
Thanks for your help, its this forum thats helped me choose the 510 over the Tom tom 300.

Hi have only just seen your message as only just joined but yes there should be plenty of room as each poi is only a few kb in size