POS Software Excel Compatible Running On a PC with Barcode Scanner

Hi ... Here is what i need

- I am running a small boutique and already have a powerful PC running in the store for other stuff ...

- I would like to get a barcode scanner which can be connected to the PC and set-up stock control + point of sale system ...

Now i am happy to provide the hardwares for this such as barcode scanner + receipt printer + PC + Cables + etc ...

All you need to do is create a software that will make me able to

1. Create barcodes and print them on A4 label papers
2. Scan the barcodes with scanner & make it minus 1 on relevant excel cell
3. Print the receipt

I can provide extra budget if you are capable of implementing all these to my online store which is run by opencart system

please ask me if there is any other questions to make sure