Oracle 11g increasing shared pool size and java pool size
You're have AMM enabled, so Oracle will manage it for you automatically. SGA_TARGET will be set to a non-zero value, which means:


  Specifies the total size of all SGA components. If SGA_TARGET is 
  specified, then the buffer cache (DB_CACHE_SIZE), Java pool 
  (JAVA_POOL_SIZE), large pool (LARGE_POOL_SIZE), and shared pool 
  (SHARED_POOL_SIZE) memory pools are automatically sized.


You can set it to a non-zero value that is equal to or less than SGA_MAX_SIZE, so if you need to allocate more memory, just up SGA_MAX_SIZE and SGA_TARGET.

eg:

ALTER SYSTEM SET SGA_MAX_SIZE = 2048M;
ALTER SYSTEM SET SGA_TARGET = 2048M;


See this documentation section (search for "Enabling Automatic Shared Memory Management") - Read that whole documentation section to gain a better understanding.

As an aside, your SGA_MAX_SIZE does seem very small.