How far up hill does the water have to run? When you say uphill do you mean from the tank thru the wall until it finally turns and falls down to the basement or do you mean from the basement to your tank?
As was described the head pressure is the big thing when sizing your pump. be cautious about the pumps from the water garden store in that they need to be rated for saltwater use. Pumps with metalic imeller shafts will cause you problems as they will rust, etc due to the saltwater. There are many saltwater designed pumps that will be able to use for this purpose.
Incase of power failure you will need to incorprorate a few items. First would be some syphon breaks on your sump return lines. This will allow air to get into the return lines and break any back syphon. But then you will have to deal with the water thats in the plumbing. Installing one or more one way flap valves should help you there in that they will thru normal operation allow water to flow only one way. When the power goes out the water will try to flow down to the basement and the one way valve will stop it. Incase that fails then you should hav some way of storing the excess water thats in the plumbing. Depending on the distance ths could be just a few gal
or it could be several gal
7 feet is not much head and you should have little problem finding a pump that can put out the GPH
that you want at 7' head. Makers of pumps will have charts on the pumps or the box's telling you what they are rated for at a given height. To baffle the water comming from 7' up you might want to introduce some creative plumbing to keep the drain lines from splashing all over the place.
ReefLady has the exact setup your talking about doing. Ill try to attract her attention to this post.
Also you might be better off with two pumps than one megga pump.