Nikkor 50mm f/1.8 Close-Up Photography?

I have a Nikkor 50mm f/1.8 lens. It has a minimal focus distance of 0.45m.
Is there a way to reduce the minimal focus distance a bit?
- I'm not interested in Auto focus (I always use the 50mm f/1.8 lens on manual focus - Nikon D3100.It is convenient for me.)
- I don't want to lose metering and aperture information.
- I would like to take photos of flowers and fill the frame (macro 1:1 not needed).
Any suggestion, please? My budget is limited. Thanks!
Added (1). Delroeki… Dude I don't need macro. I said close-up.

Nikkor 50mm f/1.8 lens is not macro capable…
Try mounting it in reverse for macro and or find available reverse couplers in market today.

A bit? Then use the close up filter. It would have to be 52 mm (to fit), but get a "weak" one.

Extension tubes are a cheap option.
You can get a nice set that will preserve your electronic aperture control.
Or you can get a dirt cheap set (I got my tubes on eBay for like $5 shipped) that doesn't. The lovely part about the Nikkor 50mm f/1.8 is that you get an aperture ring, so electronic aperture control isn't necessary.
I shoot Canon, so when I use my tubes, I have to mount the lens without tubes, set the f-stop I want to use, press the depth-of-field preview button, hold it down while twisting the lens off so the iris stays closed, THEN mount the lens on the tubes and go. It makes for a dim viewfinder when I'm trying to focus too.
What you can do instead is leave your aperture at f/1.8 while you compose, focus, etc. Then just stop it down manually to the aperture you want to shoot at. Perfect combo.
Get a set that has 3 different sized tubes that can be stacked in any order (or not stacked at all). That will give you all sorts of options for how close you can focus, ranging from slightly closer than 1:1 to barely closer than the regular minimum focus distance of the lens.

Three options.
1. Close-up filter, screws onto the front of the lens and will allow you to focus closer (but you won't be able to focus to infinity with it attached)
2. Extension tubes
3. Bellows attachment (which is pretty cool and very useful you'll be able to shoot extremely close, and depending on the type of bellows, you might even have a tilt and shift like capability, also very expensive).
I would say go with the filters or tubes (If tubes buy one's that will transfer lens info to the body, they'll cost more but will mean you can use the camera on automatic and semi-automatic settings.