So I’m guessing you are using a continuous light in that umbrella. It is rarely a good idea when it comes to people as they either don’t give off enough light or they will melt the face of the person you are photographing. A speedlight will give you far more flexibility. Personally I’m not a major fan of umbrellas either as they will spill large amounts of light everywhere. Sometimes it can be handy as it gives you ambient light as well as directional light but for the majority a couple of softboxes are going to be a better option. Umbrellas are great for learning though as they are cheap as chips.
As for your photos, I like them for most part but they leave a bit to be desired. Had they been taken with a proper camera they would have been passable as the lighting is usually interesting enough to carry the shot. First off get rid of the borrowed photo, it isn’t yours and shouldn’t be there. Second, the half naked lady with the tattoos need to go, they are not flattering shots. Sepia next to B&W is not a look that works, either or is the key. The big problem is your camera, it simply isn’t capable enough to work in this setting and you are going to have to spend a little money to progress from where you are.
First purchase should be a new camera, or rather a used camera. My suggestion for bargain basement camera would be a canon 40D in decent nick. Add to that the very decent 50mm f1.8 lens which can be had for very little. I don’t know what the used market looks like where you live but here the combo above would set you back around £200, or about twice what your powershot cost. Reason for a 40D is that they are very cheap for the performance you get from them as people don’t want 10mpix anymore which is stupid. The body is solid metal which gives it more heft which in turn makes it more stable. It has a decent autofocus system and the images from it are brilliant. Because it was positioned in the semi pro bracket when it came out it has more options than your equivalently priced rebel series camera would and also far better ergonomics.
Next purchase would be two speedlights, yongnuo 560III combined with a single yongnuo rf603 will allow you to sync the flashes wirelessly. You have one lightstand and umbrella already so you probably only need a flash bracket for that and another stand, bracket and umbrella or softbox for the other flash. The reason for the second flash is to be able to lighten shadows or provide rim light as needed. Three flashes would be ideal but obviously more expensive. White, grey and black foam board is handy to have and you can use them as light modifiers or as reflectors, especially if you glue tin foil to one of them. Each will cost a couple of dollars in A1 size which is pretty big.
If you can’t swing the light set up above a single speedlight would work, the poop up flash on the 40D will be able to fire the flash is slave mode. The speedlight you would use like you are using your lamp at the moment, except it gives you far more light.
Stick camera in manual and tweak light until you can shoot at iso 100, f8 and 1/100 (last doesn’t really matter with flash)