John is responsible for cybersecurity at a medium$-$sized manufacturing company. They have a limited budget and have implemented a basic firewall and antivirus solution. John is wondering about additional security measures he should consider.

Questions:

$1.$ What additional security measures would you recommend to John to enhance his company's cybersecurity posture within budget constraints?

$2.$ Should John consider replacing the current firewall with a different type of firewall technology? Explain your rationale.

$3.$ How can John improve the effectiveness of the antivirus solution he has in place?