Mysql Server Hanging On A High Traffic Site

My video sharing site has high traffic, alexa rate:3,000

My site has 2 servers to split the load. 2 servers share a mysql server. Using rrdns to load the balance.

Server A running mysql 5.0,lighttpd
Server B running lighttpd.
Server B connect to A's mysql database.

During peak time. B can not connect to A's mysql server. It says server not responding. But A still running fine.
When I check mysql log file.
/usr/libexec/mysqld: Forcing close of thread .....

And when run top, the load average is 20.

The spec of Server A
Intel(R) Xeon(TM) CPU 3.06GHz dual core.
2G Ram.

Here is the my.cnf

Quote:

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Default to using old password format for compatibility with mysql 3.x
# clients (those using the mysqlclient10 compatibility package).
old_passwords=1
max_connections = 1000
wait_timeout=60
connect_timeout=10
interactive_timeout=120
join_buffer_size=1M
query_cache_size=128M
query_cache_limit=2M
max_allowed_packet=16M
table_cache=1024
sort_buffer_size=2M
read_buffer_size=2M

My question, do I need another maching C to run lighttpd, and just keep mysql on A.
Or I can do some mysql optimization on A.

Also, if my site keeps going, can I have 1 mysql server and 5 http servers?