ive a new 4gb graphics card ordered and will be here in a week or 2
Which one? The amount of graphics memory does not describe the performance of the card
It's possible that your current CPU isn't causing many problems for you at the moment, a gt710 isn't capable of running modern games so it'd be a slideshow regardless of the rest of the system. That being said, the CPU is pretty old by now and lower-end at the time so a lot of games won't run well on it.
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i3/i5/i7 is not a good way to describe performance and mhz isn't either. People will generally sell it as i3 < i5 < i7 and that's usually quite true within a single CPU generation but the comparison breaks down when looking across multiple generations of releases or at laptop parts etc.
You have a first generation i3 and your upgrade option (to fit in your motherboard) would be a first generation i5 which also released ~7 years ago. It'd be a better CPU (more cores) but the CPU would be using the same technology as the one that you have and wouldn't be anywhere near as much of an upgrade as running a current gen i3 or later gen i5.
The CPU generations released since then have been increasing the performance of the CPU at the same clock speed so a 7'th generation i3 at 3ghz would be a lot faster than a 1'st generation i3 at 3ghz, that's where most of the performance increase has come from. They run at a higher frequency as well, but each mhz does a lot more work.
For gaming and some other PC tasks at a low cost i'd recommend a current gen (6xxx, 7xxx) i3 or maybe lower end i5 with new motherboard and RAM. It's possible to buy a used 4'th generation i5 and motherboard for it (like a 4670) in order to save some money and re-use the ddr3 RAM as the latest CPU's use ddr4.
AMD is releasing their new Ryzen processors very soon (likely the first days of March) which will probably be appealing, maybe even a large jump for low budget CPU performance.