Check My Mysql Config - Optimize Or Upgrade

we've currently got a 2 server setup, apache+mysql

Mysql server is a Xeon 3.2Ghz with 2Gb ram, scsi 73gb raid1 disks

Server has been running a while, steadily increasing in traffic. whilst 90% of the time it's running ok (load around 0.5 - 1.0, cpu around 25-50% busy mainly mysql, disk i/o around 3% busy) during heavy traffic times everything slows right down

At the moment the mysql box is only running mysql so we've allocated about 1.5gb out of the 2gb to mysql.

At present, when we get busy the apache server is queing up requests as it waits for the mysql server. Query log shows most queries are <1sec, any other's are being optimised but due to the nature of our website there are a few pesky queries (only occasionally being slow though).

question is, can this config be tuned any more or is it time for an upgrade - mainly ram to add more innodb buffers?

Here's the result of tuning-primer.sh

Code:
SLOW QUERIES
The slow query log is enabled.
Current long_query_time = 2 sec.
You have 9 out of 159346 that take longer than 2 sec. to complete
Your long_query_time seems to be fine

BINARY UPDATE LOG
The binary update log is enabled
The expire_logs_days is not set.
The mysqld will retain the entire binary log until RESET MASTER or PURGE MASTER LOGS commands are run manually
Setting expire_log_days will allow you to remove old binary logs automatically
See http://dev.mysql.com/doc/refman/4.1/en/purge-master-logs.html

WORKER THREADS
Current thread_cache_size = 384
Current threads_cached = 15
Current threads_per_sec = 0
Historic threads_per_sec = 0
Your thread_cache_size is fine

MAX CONNECTIONS
Current max_connections = 150
Current threads_connected = 4
Historic max_used_connections = 18
The number of used connections is 12% of the configured maximum.
Your max_connections variable seems to be fine.

MEMORY USAGE
Max Memory Ever Allocated : 1 G
Configured Max Per-thread Buffers : 5 G
Configured Max Global Buffers : 803 M
Configured Max Memory Limit : 6 G
Physical Memory : 1.99 G

Max memory limit exceeds 90% of physical memory

KEY BUFFER
Current MyISAM index space = 82 K
Current key_buffer_size = 5 M
Key cache miss rate is 1 : 1862
Key buffer fill ratio = 100.00 %
Your key_buffer_size seems to be fine

QUERY CACHE
Query cache is supported but not enabled
Perhaps you should set the query_cache_size

SORT OPERATIONS
Current sort_buffer_size = 16 M
Current read_rnd_buffer_size = 7 M
Sort buffer seems to be fine

JOINS
Current join_buffer_size = 4.00 M
You have had 0 queries where a join could not use an index properly
Your joins seem to be using indexes properly
join_buffer_size >= 4 M
This is not advised

OPEN FILES LIMIT
Current open_files_limit = 11095 files
The open_files_limit should typically be set to at least 2x-3x
that of table_cache if you have heavy MyISAM usage.
Your open_files_limit value seems to be fine

TABLE CACHE
Current table_cache value = 5467 tables
You have a total of 732 tables
You have 155 open tables.
The table_cache value seems to be fine

TEMP TABLES
Current max_heap_table_size = 255 M
Current tmp_table_size = 256 M
Of 21109 temp tables, 35% were created on disk
Effective in-memory tmp_table_size is limited to max_heap_table_size.
Perhaps you should increase your tmp_table_size and/or max_heap_table_size
to reduce the number of disk-based temporary tables
Note! BLOB and TEXT columns are not allow in memory tables.
If you are using these columns raising these values might not impact your
ratio of on disk temp tables.

TABLE SCANS
Current read_buffer_size = 7 M
Current table scan ratio = 929 : 1
read_buffer_size seems to be fine

TABLE LOCKING
Current Lock Wait ratio = 1 : 117
You may benefit from selective use of InnoDB.
If you have long running SELECT's against MyISAM tables and perform
frequent updates consider setting 'low_priority_updates=1'
Server is mainly Innodb due to previous row-locking issues.