If you want total coins, then:

146 + 812 = 958 coins

However, if you want total value...

If we consider all gold and silver coins to be roughly an ounce, then we have 146 ounces of silver and 812 ounces of gold. By today's standards, gold is worth $1078.90g (g = ounces of gold) and silver is worth $14.23s (s = ounces of silver). Simply plug in the numbers and then add it all up.

Gold: $1078.90*812 = $876066.80

Silver: $14.23*146 = $2077.58

$876066.80 + $2077.58 = $878144.38

Zoe has $878,144.38 in precious metals. In other words, she's freaking loaded and can retire happily as long as she invests wisely in the correct companies. Poor usage of her money will lead to her being penniless in a matter of weeks and she will be homeless and lamenting her fate.

EDIT: I've just realized this is my 250th answer. Oh joy.