Site Gonna Slow and Too much

My is gone too much slow with the theme and there are many fatal error some tile an some times its work fine ! why i am useing vps for my site vps ram gone to totall uses when site run down!! what can i do to fixt that ? i talked with vps support they talking that the problm is on theme not in vps!! see some screen shoot here of those error and help me out.
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servermania says
Staff
From: Jeff C. Sent to Dario Busch on Dec/16/2015 9:34:50AM
Hello,
Your VPS is using up a considerable amount of resources causing the node to
reach high server load. Please resolve this within the next 5 minutes to avoid
suspension.
23.236.147.11
top – 09:32:14 up 4 days, 6:04, 0 users, load average: 137.91, 132.48,
101.71
Tasks: 342 total, 139 running, 195 sleeping, 0 stopped, 8 zombie
Cpu(s): 96.8%us, 3.2%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4194304k total, 4191980k used, 2324k free, 0k buffers
Swap: 4194304k total, 3894628k used, 299676k free, 13776k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27415 db101 20 0 222m 54m 4684 R 6.0 1.3 0:00.81 php
27110 db101 20 0 222m 18m 4468 R 5.6 0.5 0:03.90 php
26803 db101 20 0 233m 31m 4400 R 3.3 0.8 0:07.73 php
27159 db101 20 0 216m 17m 4532 R 1.7 0.4 0:04.00 php

errors happen some times not full time ??

internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator at [email protected] to inform them of the time this error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log.
Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator at [email protected] to inform them of the time this error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log.
Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Is there any paid option ? if need i will buy this theme.:)
Thanks