The simplest way to do it is to plug a USB memory stick into your laptop. (If you've not already got one, and can't simply borrow one, Asda sell them cheaply
http://groceries.asda.com/product/data-storage/sandisk-cruzer-blade-8gb-usb-flash-drive/910000422616 ).
Accept the option to 'Open folder to view files'. (If it doesn't come up, go to 'Computer' and double-click on the icon for the USB drive). If the window fills the screen, make it smaller by clicking on the overlapping squares, at the top right, to make it smaller
Open 'My Pictures' (or whatever other folder you've got the images saved into), once again ensuring that the window doesn't fill the screen.
You've now got two windows open side by side, meaning that you can simply drag-&-drop files from one window to another. (To select a whole block of files for dragging, click on the first one and then hold the Shift key down while clicking on the last one. To select lots of separate files as a group, click on each one in turn while holding Ctrl down).
Remove the USB stick safely (by using the appropriate icon at the bottom right hand of the screen). Insert it into your sister's laptop and go through the process again, this time dragging-&-dropping from the USB stick to 'My Pictures' (or wherever).
Alternatively, open a free email account here:
http://www.gmx.co.uk
You don't have to use it for email but it does give you free storage space. Log into your account. Click on 'File Storage'. Create a new folder called 'Pictures' (for example). Open it to display its (non-existent) contents. Click 'Add files'. Navigate to 'My Pictures' (or wherever). Select all the relevant files (using Shift or Ctrl, as above). Click on 'Open'. Your pictures will then be uploaded to your storage space. (Be patient. 70 pics will take a while!). Then select the option to email a gust link to your sister, so that she can access the file and download the pictures.