Upgrade to oval?!

[Jennifer88]

Hi everyone! Looking for some advice here in an engagement ring upgrade.
My current ring (pictured) is a 0.7 J colored vvs2 round stone. I'd like to trade in this diamond and with a budget of $3-4 usd, upgrade to a 1+ carat stone with better color and go down on the clarity to fit my budget. I've always loved ovals and the look of more finger coverage and hoping to work with a jeweler who can use the band of my current setting and create a new top for a larger oval halo. It seems like my budget will be tight for this, but does is it reasonable? Am I best to shop in person for an oval stone so I can see with my own eyes or will I get better prices online? An alternative option is to leave my ring as is and use our budgeted money to buy another wedding band...although I love the idea of upgrading my ring, I just want it to look different enough that this is worth it and don't know if my budget will allow me to get a stone large enough to really look different than what I have. Looking for some advice, guidance and opinions as I go through this shopping process! Thank you so much in advance!

Any suggestions are appreciated.