You should have thought of all of those jobs back when you were siding with the protestors against our using that base for naval practice.
No naval practice means no need for a naval base there, genius...
The base closing is indeed a situation that will adversely affect Puerto Rico's economy significantly.
And disposition of the base property should be monitored closely for corrupt political influences.
That said, there should be action taken to offset the negative economic impact of this decision. Rather than expansion of government welfare programs, I would prefer to see government investment in infrastructure that would both provide short term employment opportunities and long term development of private commerce.
As an island economy with limited natural resouces, there are special considerations to be taken in this respect. Chief among these would be energy policy. Puerto Rico currently generates 99.22% of its electricity from fossil fuel (the 0.78% balance is hydroelectric.) It should be relatively easy to displace this dependence on fossil fuel with a combination of nuclear, wind and solar sources.
Similary, Puerto Rico often suffers from limited fresh water availability, so development of desalination facilities would seem appropriate. (Along with any necessary wastewater treatment systems.)
Lastly, to improve transportation infrastructure on the island, construction of a modern, efficient, electric light-rail passenger system should be considered. (The island is too small to benefit from any kind of interstate highway system and/or high-speed rail or maglev).
Ooooops! Did I say "lastly"???
There is one more thing: Both Congress and Dubya should do a little arm twisting of Major League Baseball to locate a permanent franchise in San Juan. Such a move would be good, both for baseball and the Puerto Rican tourist industry.