Each relay draws about 90mA (according to my measurements), so theoretically it is possible to use as many as 2 relays simultaneously, given that Arduino's Vcc pin can source 200mA max (refer here for your board's limitations).
You are misunderstanding that 200ma max current rating. The 200ma limit is the total you can draw from all the output pins at any single time, as it's a current limit inside the 328P chip. The limit on the shield 5V pin depends on how you are powering the board. If from USB power the 5V pin can source up to around 400ma or so (limited by the 500ma thermfuse), less the total current being drawn from the output pins. If being powered from the external DC connector you can usually get a could of hundred MA above that from the on-board 5 volt regulator.