Oracle / sql : calculation one or more value within the same field

1- I want select statement to sum the amount of value 352+652+20+356 that come in the same filed without need PL/SQL .

[{Name:"account:account_1"&Value:352&New:256&CreditLimit:0} {Name:"account:account_2"&Value:652&New:369&CreditLimit:0} {Name:"account:account_3"&Value:20&New:3256&CreditLimit:0} {Name:"account:account_4"&Value:356&New:6589&CreditLimit:0}]

2- I want function to SUBSTR ever thing after : if Letter or number or mark. OfferId:test OfferId:790

OfferId:test-345-new OfferId:offer345