Robb, I know you want to maximize your security with XP. You want level headed answers. So, that is what I am going to give you.
First, you are talking about XP. I know nothing about you, your age, etc. But, I do know when XP first came out, it was met with resistance. It wasn't until the first service pack (SP 1) that people began to like XP. It was too different, hardware and software was not compatible. By the time SP 1 came out, hardware and software was becoming compatible. We learned to like XP. But, there were still Win 98 holdouts. Eventually, they came on board. Then Vista came out, and everyone hated it. For the exact same reasons they hated XP. It was different, and nothing was compatible, Win 7 came out, and it was received well, but, thats because people's hardware and software was (for the most part) compatible to Vista. Those who (for the most part) loved 7, but, hated Vista, did not realize this. Now we are Windows 8, and about 18 months away from Windows 9. So, you ask how to secure Windows XP. Level-headedly.
Sorry to say this, but, anything you do will be very temporary. My suggestion is to begin now getting ready for Windows 8 and even 9. Or, if you are fed up with MS, you can try Linux or Mac. Linux will be cheaper, but, most likely more complicated than you may want to deal with. Mac will definitely be more expensive, but it will be compatible with all things Mac.
There's a lot of "fanboy" crap out there. I try to ignore it all. There's only one person you need to care about being a fan of anything. That is you. You can continue with XP, but, there will be problems down the line. As you are reading, and asking, security. But, as hardware breaks down, you have to ask, will new products be compatible with XP? Software. As new software comes out, and you want new programs, will they work on XP? Security programs. I see you are using free security programs. People suggest AVG and Avast as two "great" free programs. I've not been impressed with either. If you want free software, there's better ways to get paid security software for free. One is to go to their website, and see if they are part of TrialPay. They offer full version software for free, for trying other products.
Don't like that idea? During tax season, Office Max, Office Depot, and/or Staples tend to offer free security (and other useless software) for free with the purchase of any tax software (after rebate). Some stores offer rebates on software on a regular basis (Fry's electronics for one. Google them for their website).
<div>My point is, you can get better security programs for free, if you hunt them down. Just make sure you get rid of the old security programs (Kaspersky tells you what is not compatible, and if there's still bits hiding in your computer). My other point is, take the time to patiently get a new updated computer. You still have more than half a year before MS stops it's updates. And then another month before their next update would have been released.
But, consider asking yourself this question: With security issues growing by leaps and bounds each and every year, do you REALLY want to trust your security at the hands of free? And, when you ask yourself this, ask what exactly are you wanting security to do? Ultimately, to keep you safe from predators, identity theft, and people who just like to reek havoc on your system. Is it worth it to continue gambling with free software, or, invest in companies that get paid to protect you? As I said, there are ways to get the paid software free, but, you have to do your homework. </div>
So, my advice to you is, understand your budgetary limits, but, also understand what is at risk by staying with XP. Again, sorry to say this, but, unfortunately, it's what you probably need to hear, the most.