Coming into this thread new.. it'* very confusing.
There are two cars in your sig and this is in the "other 3800 powered cars". This should be you are talking about the Park Ave, is that correct?
First thing to do is pull that access cover and diagnose where the leak is located. Right now you don't appear to know if this is a broken or punctured fuel line, a leak in the tank or a bad seal on the pump/soleniod unit.
Pull the access cover in the trunk to get a better diagnosis of what is leaking. Without inspecting, all our diagnosis could be so far out of left field that we may be in another country.