help with Shipping Calculatoins

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Hello there.
I am a website developer and Zen Cart newbie. My client wants to ship using the following critereia. With her current shopping cart she has it setup this way with Paypal doing the shipping calculations and it is working good for her. Unfortunately I found out that I can't disable the Zen Cart shipping and just let it defer to paypal. Now I need to set it up in Zen Cart and disable the Paypal shipping. The solutions isn't very clear to me.

East of the Mississippi States:

Tiered rates based on order amount. For example:

$0.01 to $75.00 is $8.95 shipping
$75.01 to $125.00 is $10.95
$125.01 to $175.00 is $12.95
$175.01 to $225.00 is $15.95
$225.01 to $300.00 is $18.95
$300.01 And up is $30.00

West of the Mississippi States:

Tiered rates based on amount similar but slightly different to the example above.

Canada:

Also has a tiered table based on price.

International: Needs ability to block certain countries

Based on total price table like all examples above.

Question: Can I accomplish this with the installed Shipping Modules or am I going to have to find a plugin or something. If so, any suggestions?

Thanks!
Kim